determining the deformations in western anatolia with...
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DOKUZ EYLÜL UNIVERSITY
GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES
DETERMINING THE DEFORMATIONS IN
WESTERN ANATOLIA WITH GPS AND
GRAVITY MEASUREMENTS
by
Ayça ÇIRMIK
November, 2014
İZMİR
DETERMINING THE DEFORMATIONS IN
WESTERN ANATOLIA WITH GPS AND
GRAVITY MEASUREMENTS
A Thesis Submitted to the
Graduate School of Natural and Applied Sciences of Dokuz Eylül University
In Partial Fulfillment of the Requirements for the Degree of Doctor of
Philosophy in Geophysical Engineering
by
Ayça ÇIRMIK
November, 2014
İZMİR
Ph.D. THESIS EXAMINATION RESULT FORM
We have read the thesis entitled “DETERMINING THE DEFORMATIONS IN
WESTERN ANATOLIA WITH GPS AND GRAVITY MEASUREMENTS”
completed by AYÇA ÇIRMIK under supervision of PROF. DR. ZAFER AKÇIĞ
and we certify that in our opinion it is fully adequate, in scope and in quality, as a
thesis for the degree of Doctor of Philosophy.
Prof. Dr. Zafer AKÇIĞ
Supervisor
Prof. Dr. Mustafa AKGÜN Prof. Dr. Hasan SÖZBİLİR
Thesis Committee Member Thesis Committee Member
Prof. Dr. Ferruh YILDIZ Doç. Dr. Oya PAMUKÇU
Examining Committee Member Examining Committee Member
Prof.Dr. Ayşe OKUR Director
Graduate School of Natural and Applied Sciences
ii
ACKNOWLEDGMENTS
The GPS data (stations of CORS-TR project and General Command of Mapping)
were obtained by Dokuz Eylul University Scientific Research project,
2012.KB.FEN.126.
First of all, I would like to thank my supervisor, Prof. Dr. Zafer AKÇIĞ for his
helps and advices on Ph.D. thesis and Assoc. Prof. Dr. Oya PAMUKÇU for her
suggestions, helps and encouraging and being near me whenever I need during my
all graduate career. I would like to thank members of Ph.D. committee, Prof. Dr.
Müjgan ŞALK and Prof. Dr. Hasan SÖZBİLİR and members of examining
committee, Prof. Dr. Ferruh YILDIZ and Prof. Dr. Mustafa AKGÜN for their
advices for improving the thesis. I am grateful and would like to thank Asst. Prof. Dr.
Tolga GÖNENÇ for his advices and lots of helps. I would like to thank Assoc. Prof.
Dr. Muzaffer KAHVECİ for introducing me with GPS measurements and for his
advices on processing GPS data.
I would like to thank Prof. Dr. Carla BRAITENBERG for her advices and helps
on my research when I was at Trieste University as an Erasmus exchange student and
Jean CHERY for helping me numerical modeling when I was at Montpellier
University. I would like to thank Assoc. Dr. Uğur DOĞAN for improving my
knowledge about geodesy by following his graduate lesson at Yıldız Technical
University, Department of Geomatic Engineering. I would like to thank Prof. Dr.
Bradford Hager for helping me on my research and improving myself by following
his graduate lessons when I was at MIT as the Council of Higher Education scholar. I
would like to thank Prof. Dr. Thomas HERRING and Dr. Bob KING for their
precious advices and answering my questions about GAMIT/GLOBK software,
patiently. I am grateful to Asst. Prof. Dr. Mickael BONNIN for his helps on
processing on ADELI software. I would like to thank Assoc. Prof. Dr. Mehmet
ERGIN and other members of The Scientific and Technological Research Council of
Turkey (TUBITAK), Marmara Research Center, Earth and Marine Science Institute
iii
for helping on providing the GPS data of TURDEP project. I would like to thank the
project manager, Assoc. Prof. Dr. Oya PAMUKÇU and all researchers of TUBITAK
project, No:108Y285 for allowing me to use the GPS results of the project.
I would like to thank my professors and colleagues at Dokuz Eylül University,
Departments of Geophysical and Geological Engineering. I wish to thank all
members of Student Affairs Department of Dokuz Eylul University, Graduate School
of Natural and Applied Science for answering to all my questions patiently during
graduate career.
Finally, but at the top of the list, I thank my dear parents, Sevil & Muammer
YURDAKUL and my dear brother Tolga YURDAKUL for encouraging me at all my
life and being near and helping me in my long academic career. I thank my dear
mother-in-law Semra ÇIRMIK for creating a study environment during the writing of
my thesis. I thank my dear husband Ömer for his unwavering support and
encouragement, not just during the writing of this thesis, but throughout my
undergraduate and graduate career. Finally, I wish to thank my dear son Yiğit
ÇIRMIK for being the meaning of my life. I wish to dedicate my thesis to my dear
family.
Ayça ÇIRMIK
iv
DETERMINING THE DEFORMATIONS IN WESTERN ANATOLIA WITH
GPS AND GRAVITY MEASUREMENTS
ABSTRACT
Western Anatolia is one of the most seismically active and rapidly extending
regions in the world and is currently experiencing an approximately N–S continental
extension. Due to this important case of Western Anatolia, deformations of the
region were examined by GPS and gravity measurement in this study.
Firstly, the GPS stations of TURDEP poject, CORS-TR Project and General
Command of Mapping were processed relative to Eurasia fixed frame and the
velocities of the stations were found as approximately 20-25 mm per year. Besides,
the Anatolian Block and Aegean block solutions the velocity magnitudes were
obtained between approximately 3-15 mm per year. As second step, the GPS and
microgravity data, which were obtained simultaneously at 6 points; Akhisar
(Manisa), Eşme (Uşak), Çal (Denizli), Bademli (İzmir), Borlu (Manisa), Karacasu
(Aydın), were compared for discussing about vertical mass changes on the
measurement points. As third step, obtained GPS velocities by using GAMIT-
GLOBK software were compared with the modeled GPS velocities by Coulomb 3.3
software on the northern normal fault of Gediz graben and southern normal fault of
the Büyük Menderes graben by using Coulomb 3.3 software and coulomb stress
changes were obtained for these faults and compared with earthquakes. As the last
step, the numerical models were created by using finite elements for determining the
deformation of Western Anatolia during the geological time scales.
As a result, all the results were compared with the previous geophysical and
geological studies and earthquake focus depth distributions.
Keywords: Western Anatolia, GPS, gravity, coulomb stress changes, numerical
modeling, finite elements.
v
BATI ANADOLU BÖLGESİNDEKİ DEFORMASYONLARIN GPS VE
GRAVİTE ÖLÇÜMLERİ İLE BELİRLENMESİ
ÖZ
Batı Anadolu dünyadaki sismik olarak çok aktif ve ani açılma gösteren
bölgelerden biridir ve halen yaklaşık K-G yönünde kıtasal açılma göstermektedir.
Batı Anadolu bölgesinin bu önemli durumundan dolayı, bu çalışmada bölgedeki
deformasyonları irdelemek için GPS ve mikrogravite ölçümleri kullanılmıştır.
İlk olarak TURDEP, TUSAGA-AKTİF ve Harita Genel Komutanlığı’ndan temin
edilen GPS verileri Avrasya sabit çözümler ile proses edilmiş, yılda yaklaşık 20-25
mm'lik hızla hareket ettiği saptanmıştır. Ayrıca, rejyonel deformasyonu gözlemlemek
için Ege ve Anadolu blok çözümleri yapılmıştır ve istasyonların hız değişimleri
yaklaşık yılda 3-15 mm olarak saptanmıştır. İkinci adımda, 6 noktada Akhisar
(Manisa), Eşme (Uşak), Çal (Denizli), Bademli (İzmir), Borlu (Manisa), Karacasu
(Aydın), eşzamanlı olarak alınmış GPS ve mikrogravite verileri, düşey yöndeki kütle
değişimini irdelemek için birlikte değerlendirilmiştir. Üçüncü adımda, Gamit-Globk
yazılımı ile elde edilen GPS hızları ile Coulomb 3.3 yazılımıyla modellenen GPS hız
verileri Gediz grabeninin kuzeyindeki normal fay ve Büyük Menderes Grabeninin
güneyindeki normal fay için birlikte değerlendirilmiş ve bu faylardaki Coulomb stres
değişimi elde edilmiştir. Son olarak jeolojik dönemler boyunca Batı Anadolu
bölgesindeki deformasyonu incelemek için sonlu elemanlar yöntemi ile bölgeye ait
sayısal modelleme yapılmıştır.
Sonuç olarak, bu çalışmada elde edilen tüm bulgular, çalışma alanında yapılmış
jeofizik ve jeolojik çalışmaların sonuçlarıyla ve deprem odak derinlik dağılımları ile
karşılaştırılmıştır.
Anahtar Kelimeler: Batı Anadolu, GPS, gravite, coulomb stres değişimleri, sayısal
modelleme, sonlu elemanlar.
vi
CONTENTS
Page
THESIS EXAMINATION RESULT FORM .............................................................. ii
ACKNOWLEDGEMENTS ........................................................................................ iii
ABSTRACT ................................................................................................................ .v
ÖZ ............................................................................................................................... vi
LIST OF FIGURES ..................................................................................................... x
LIST OF TABLES .................................................................................................... xix
CHAPTER ONE – INTRODUCTION .................................................................... 1
CHAPTER TWO – GEOLOGY OF THE STUDY AREA .................................... 4
CHAPTER THREE – DEFORMATION ESTIMATIONS WITH GPS
PROCESSING ............................................................................................................ 8
3.1 The Segments of GPS........................................................................................ 8
3.1.1 The Space Segment.................................................................................... 9
3.1.2 The Control Segment. .............................................................................. 10
3.1.3 The User Segment.................................................................................... 11
3.2 Reference Coordinate System of GPS ............................................................. 11
3.2.1 Earth-Centered Inertial (Space-fixed) (ECI) Coordinate System. ........... 12
3.2.2 Earth-Centered Earth-Fixed (ECEF) Coordinate System ........................ 12
3.2.3 World Geodetic System-1984 (WGS-84) ................................................ 13
3.3 Sources of Errors ............................................................................................. 13
3.3.1 Ephemeris (Orbital Position) Errors ........................................................ 13
3.3.2 Satellite and Receiver Clock Errors ......................................................... 13
3.3.3 Atmospheric Effects ................................................................................ 14
3.3.4 Selective Availability............................................................................... 15
3.3.5 Multipath.................................................................................................. 15
3.3.6 Receiver Antenna Phase Center Error ..................................................... 16
vii
3.4 Differential Observations Based on GPS Measurements ................................ 16
3.4.1 Single Differences ................................................................................... 16
3.4.2 Double Differences .................................................................................. 17
3.4.3 Triple Differences .................................................................................... 17
3.5 The Principle of GPS Measurement ................................................................ 17
3.5.1 The Principle of Phase Measurement ...................................................... 19
3.6 Data Processing Steps ..................................................................................... 24
3.6.1 Processing: The Three-Step Method ....................................................... 24
3.6.2 Pre-Processing Steps ................................................................................ 26
3.6.3 Processing Steps ...................................................................................... 27
3.6.3.1 Processing Steps of GAMIT Program ............................................. 27
3.6.3.2 Processing Steps of GLOBK Program ............................................. 28
3.7 The Applications ............................................................................................. 30
3.7.1 Other Relatively Solutions ....................................................................... 72
3.7.1.1 Anatolian Block Solutions ............................................................... 73
3.7.1.2 Aegean Block Solutions ................................................................... 76
CHAPTER FOUR – ANALYZING MASS CHANGES OF WESTERN
ANATOLIA BY USING MICROGRAVITY AND GPS DATA ......................... 78
4.1 Applications ..................................................................................................... 81
4.1.1 GPS data Processing ................................................................................ 81
4.1.2 Comparison of GPS and Microgravity Results ....................................... 90
CHAPTER FIVE - COULOMB STRESS CHANGES CALCULATIONS ..... 105
5.1 Applications ................................................................................................... 107
5.1.1 Northern Normal Fault of Gediz Graben ............................................... 108
5.1.2 Southern Normal Fault of Büyük Menderes Graben ............................. 117
5.1.3 The Relative Calculations on Study Area .............................................. 125
viii
CHAPTER SIX - NUMERICAL MODELING .................................................. 129
6.1 Physical Problem (continuum) and Equilibrium Equations. ........................ 129
6.2 Constitutive Laws .......................................................................................... 131
6.2.1 Elastoplasticity ....................................................................................... 132
6.2.2 Viscoelasticity........................................................................................ 133
6.3 General Algorithm of the Finite Element Modeling Software (ADELI) ..... 134
6.4 Applications ................................................................................................... 135
CHAPTER SEVEN - CONCLUSIONS ............................................................... 156
REFERENCES ....................................................................................................... 161
ix
LIST OF FIGURES
Page
Figure 2.1 Simplified tectonic map of Turkey showing major neotectonic structures
and neotectonic provinces. Red square shows the study area ................... 4
Figure 3.1 GPS segments ............................................................................................. 9
Figure 3.2 The space segment of GPS ....................................................................... 10
Figure 3.3 The control segment of GPS ..................................................................... 11
Figure 3.4 Sources of signal interference ................................................................... 16
Figure 3.5 General classifications of GNSS Positioning methods ............................. 19
Figure 3.6 Principle of GPS phase measurement ....................................................... 22
Figure 3.7 The GPS stations are located Western Anatolia ....................................... 32
Figure 3.8 The GPS stations which used in the study are shown in general tectonic
structures map of Western Anatolia ........................................................ 33
Figure 3.9 The IGS stations which used in processing are shown by red circle ...... 36
Figure 3.10 The processing solutions of AYD1 for the days between 180th-195th of
the years between 2009-2011 .................................................................. 37
Figure 3.11 The processing solutions of BALK for the days between 180th-195th of
the years between 2009-2011 .................................................................. 38
Figure 3.12 The processing solutions of CESM for the days between 180th-195th of
the years between 2009-201 .................................................................... 39
Figure 3.13 The processing solutions of DEIR for the days between 180th-195th of
the years between 2009-2011 .................................................................. 40
Figure 3.14 The processing solutions of DENI for the days between 180th-195th of
the years between 2009-2011 .................................................................. 41
Figure 3.15 The processing solutions of HARC for the days between 180th-195th of
the years between 2009-2011 .................................................................. 42
Figure 3.16 The processing solutions of IZMI for the days between 180th-195th of
the years between 2009-2011 .................................................................. 43
Figure 3.17 The processing solutions of KIKA for the days between 180th-195th of
the years between 2009-2011 .................................................................. 44
x
Figure 3.18 The processing solutions of MUGL for the days between 180th-195th of
the years between 2009-2011 .................................................................. 45
Figure 3.19 The processing solutions of SALH for the days between 180th-195th of
the years between 2009-2011 .................................................................. 46
Figure 3.20 The processing solutions of USAK for the days between 180th-195th of
the years between 2009-2011 .................................................................. 47
Figure 3.21 The processing solutions of AKHT for the days between 180th-195th of
the years between 2009-2011 .................................................................. 48
Figure 3.22 The processing solutions of BDMT for the days between 180th-195th of
the years between 2009-2011 .................................................................. 49
Figure 3.23 The processing solutions of BORT for the days between 180th-195th of
the years between 2009-2011 .................................................................. 50
Figure 3.24 The processing solutions of CALT for the days between 180th-195th of
the years between 2009-2011 .................................................................. 51
Figure 3.25 The processing solutions of ESMT for the days between 180th-195th of
the years between 2009-2010 .................................................................. 52
Figure 3.26 The processing solutions of IZMT for the days between 180th-195th of
the years between 2009-2011 .................................................................. 53
Figure 3.27 The processing solutions of KRCT for the days between 180th-195th of
the years between 2009-2011 .................................................................. 54
Figure 3.28 The processing solutions of KRPT for the days between 180th-195th of
the years between 2009-2011 .................................................................. 55
Figure 3.29 The processing solutions of TRBT for the days between 180th-195th of
the years between 2009-2011 .................................................................. 56
Figure 3.30 WRMS values for North-East-Up directions from combination of
TURDEP and CORS-TR projects stations for 2009, 2010 and 2011...... 57
Figure 3.31 WRMS values for North (N)-East(E)-Up(U) directions from
combination of IGS for the days between 180th-195th of 2009, 2010
and 2011 .................................................................................................. 58
Figure 3.32 The processing solutions of BAYO for 261st and 262nd days of 2000,
211st and 212nd days of 2001, 123rd and 124th days of 2005 ............ 59
xi
Figure 3.33 The processing solutions of CEIL for 271st and 272nd days of 2000,
211st and 212nd days of 2001 .............................................................. 60
Figure 3.34 The processing solutions of CKOY for 208th and 209th days of 2001,
212nd and 213rd days of 2004 ............................................................. 61
Figure 3.35 The processing solutions of EMET for 271st and 272nd days of 2000,
123rd and 124th days of 2005 .............................................................. 62
Figure 3.36 The processing solutions of LTFY for 89th day of 2000, 97th and 297th
days of 2001 and 157th and 158th days of 2004 .................................. 63
Figure 3.37 The processing solutions of YENF for 258th and 259th days of 2000,
214th and 215th days of 2001 .............................................................. 64
Figure 3.38 The processing solutions of ZEYT for 211st and 212nd days of 2001,
212nd and 213rddays of 2004 ............................................................... 65
Figure 3.39 WRMS values for North-East-Up directions from combination of
General Command Mapping stations for 2000, 2001, 2004 and 2015 66
Figure 3.40 WRMS values for North-East-Up directions from combination of IGS
stations for 2000, 2001, 2004 and 2015 ............................................... 66
Figure 3.41 GPS horizontal velocities and their 95% confidence ellipses in a Eurasia
fixed reference frame for the period of 2009-2011 for TURDEP and
CORS-TR stations which are shown by red vectors and for the period of
2000-2001-2004 and 2005 for General Command Mapping stations
which are shown by green vectors ........................................................ 69
Figure 3.42 a) GPS horizontal velocities of the study McClusky et al. (2000) for the
period 1988-1997 and GPS horizontal velocities of the TUBITAK
project No:108Y285 for the period 2009-2011 with 95% confidence
ellipses in a Eurasia fixed frame are added to the study area stations
given in Figure 3.41 ............................................................................... 70
Figure 3.42 b) The stations which were given at Figure 3.42.a were separated to4
regions ................................................................................................... 71
Figure 3.43 a) The velocity field with 95% confidence ellipses of the stations
computed in Anatolian block frame from 3-year (2009, 2010 and 2011)
GPS data ............................................................................................... 74
xii
Figure 3.43 b) The stations are grouped to 3 regions and shown by red shapes. Line
A shows the boundary of North Anatolian Region (NAR). Line B
shows the separation of the group 1 and 2 ............................................ 75
Figure 3.44 Geological map of Western Anatolia and its surrounding...................... 76
Figure 3.45 The velocity field with 95% confidence ellipses of the stations computed
in Aegean fixed reference frame from 3-year (2009, 2010 and 2011) GPS
data .......................................................................................................... 77
Figure 4.1 a) General tectonic of the Turkey NAFZ: North Anatolian Fault Zone,
WAEP: Western Anatolian Extensional Zone EAFZ:Eastern Anatolian
Fault Zone. b) The locations of GPS and microgravity stations ............. 80
Figure 4.2 WRMS repeatabilities of North-East-Up values from combination of
2007, 2008 and 2009 GPS data ............................................................... 82
Figure 4.3 The daily processing results (between the days 139th and 142nd) of
AKHT stations between the years 2007 and 2009 .................................. 83
Figure 4.4 The daily processing results (between the days 139th and 142nd) of
BORT stations between the years 2007 and 2009................................... 84
Figure 4.5 The daily processing results (between the days 139th and 142nd) of
ESMT stations between the years 2007 and 2009.................................. 85
Figure 4.6 The daily processing results (between the days 139th and 142nd) of
CALT stations between the years 2007 and 2009 ................................... 86
Figure 4.7 The daily processing results (between the days 139th and 142nd) of
BDMT stations between the years 2007 and 2009 .................................. 87
Figure 4.8 The daily processing results (between the days 139th and 142nd) of
KRCT stations between the years 2007 and 2009................................... 88
Figure 4.9 GPS horizontal velocities and their 95% confidence ellipses in a Eurasia-
fixed reference frame for the period of 2007-2009 ................................. 89
Figure 4.10 a) Gravity changes of AKHT stations between the years 2007-2009 b)
Displacement changes on vertical direction of AKHT stations between
the years 2007-2009 ................................................................................ 91
Figure 4.11 a) Gravity changes of BDMT stations between the years 2007-2009 b)
Displacement changes on vertical direction of BDMT stations between
the years 2007-2009 ................................................................................ 91
xiii
Figure 4.12 a) Gravity changes of KRCT stations between the years 2007-2009 b)
Displacement changes on vertical direction of KRCT stations between
the years 2007-2009 ................................................................................ 92
Figure 4.13 a) Gravity changes of BORT stations between the years 2007-2009 b)
Displacement changes on vertical direction of BORT stations between
the years 2007-20099 .............................................................................. 92
Figure 4.14 a) Gravity changes of CALT stations between the years 2007-2009 b)
Displacement changes on vertical direction of CALT stations between
the years 2007-2009 ................................................................................ 93
Figure 4.15 a) Gravity changes of ESMT stations between the years 2007-2009 b)
Displacement changes on vertical direction of ESMT stations between
the years 2007-2009 ................................................................................ 93
Figure 4.16 The Earthquakes distributions which occurred between the years 2005-
2014 ......................................................................................................... 95
Figure 4.17 a) Topographic map of study area b) The blue lines show the cross-
sections .................................................................................................... 96
Figure 4.18 a) The topographic changes along to cross-section A-A' b) Earthquake
distributions along to S-N direction near to AKHT station. Small Red
square shows the location of the station .................................................. 97
Figure 4.19 a) The topographic changes along to cross-section B-B' b) Earthquake
distributions along to S-N direction near to BDMT station. Small Red
square shows the location of the station .................................................. 97
Figure 4.20 a) The topographic changes along to cross-section C-C' b) Earthquake
distributions along to S-N direction near to KRCT station. Small Red
square shows the location of the station .................................................. 98
Figure 4.21 a) The topographic changes along to cross-section D-D' b) Earthquake
distributions along to S-N direction near to BORT station. Small Red
square shows the location of the station .................................................. 98
Figure 4.22 a) The topographic changes along to cross-section E-E' b) Earthquake
distributions along to S-N direction near to CALT station. Small Red
square shows the location of the station .................................................. 99
xiv
Figure 4.23 a) The topographic changes along to cross-section F-F' b) Earthquake
distributions along to S-N direction near to ESMT station. Small Red
square shows the location of the station .................................................. 99
Figure 5.1 The axis system used for Coulomb stresses calculations of on optimum
failure planes ......................................................................................... 106
Figure 5.2 The parameters of fault geometry ........................................................... 108
Figure 5.3 GPS velocities of North stations (AKHT, BORT, ESMT and CALT) and
South stations (TRGT and SALH ) relative to each other .................... 109
Figure 5.4 Blue vectors represent the obtained GPS velocities by Gamit/Globk and
red vectors represent modeled GPS velocities by Coluomb 3.3 ........... 110
Figure 5.5 The view of ‘stress control panel’ of Coulomb 3.3 software for calculating
Coulomb Stress Changes for the northern normal fault of Gediz Graben
at 6 km depth ......................................................................................... 111
Figure 5.6 a) Coulomb stress changes between the depth of 0-4 km b) Earthquake
focus distributions on the study area. USGS earthquake archive was used
between the years 1970-2014 ................................................................ 112
Figure 5.7 a) Coulomb stress changes at depth 4 km b) Earthquake focus
distributions on the study area. USGS earthquake archive was used
between the years 1970-2014 ................................................................ 113
Figure 5.8 a) Coulomb stress changes between the depth of 0-6 km b) Earthquake
focus distributions on the study area. USGS earthquake archive was used
between the years 1970-2014 ................................................................ 114
Figure 5.9 a) Coulomb stress changes at depth 6 km b) Earthquake focus
distributions on the study area. USGS earthquake archive was used
between the years 1970-2014 ................................................................ 115
Figure 5.10 GPS velocities of North stations (AYD1, BDMT and CALT) and South
stations (KRPT, KRCT and DENI ) relative to each other ................... 118
Figure 5.11 Blue vectors represent the obtained GPS velocities by Gamit/Globk and
red vectors represent modeled GPS velocities by Coluomb 3.3 ........... 118
Figure 5.12 The view of ‘stress control panel’ of Coulomb 3.3 for calculating
Coulomb stress Changes for the Southern normal fault of Büyük
Menderes Graben at 3 km depth ......................................................... 119
xv
Figure 5.13 a) Coulomb stress changes between the depth of 0-3 km b) Earthquake
focus distributions on the study area. USGS earthquake archive was used
between the years 1970-2014 ................................................................ 120
Figure 5.14 a) Coulomb stress changes at 3 km depth b) Earthquake focus
distributions on the study area. USGS earthquake archive was used
between the years 1970-2014 ................................................................ 121
Figure 5.15 a) Coulomb stress changes between the depth of 0-5 km b)
Earthquake focus distributions on the study area. USGS earthquake
archive was used between the years 1970-2014.................................... 122
Figure 5.16 a) Coulomb stress changes at 5 km depth b) Earthquake focus
distributions on the study area. USGS earthquake archive was used
between the years 1970-2014 ................................................................ 123
Figure 5.17 GPS velocities of left side stations (KIKA, AKHT and TRGT shown by
black vectors) and right side stations (DEIR, BORT, USAK and ESMT
shown by red vectors) relative to each other ......................................... 126
Figure 5.18 GPS velocities of left side stations (KIKA, AKHT and TRGT shown by
black vectors) and right side stations (USAK and ESMT shown by red
vectors) relative to each other ............................................................... 126
Figure 5.19 GPS velocities of left side stations (KIKA, AKHT, TRGT, DEIR and
BORT shown by black vectors) and right side stations (USAK and
ESMT shown by red vectors) relative to each other ............................. 127
Figure 5.20 GPS velocities of left side stations (BDMT, AYD1 and KRPT shown by
black vectors) and right side stations (CALT, KRCT and DENI shown by
red vectors) relative to each other ......................................................... 128
Figure 6.1 a) The model of elastoplastic material b) The deformation of elastoplastic
material due to stress ............................................................................. 132
Figure 6.2 a) The model of viscoelastic material b) The behavior of the viscoelastic
solid ....................................................................................................... 133
Figure 6.3 The simple model created with 'gmsh' .................................................... 136
Figure 6.4 The view of 3D meshing with 'gmsh' ..................................................... 136
Figure 6.5 The view of initial model. Green arrows represent the extensional forces
were given the borders .......................................................................... 137
xvi
Figure 6.6 The view of finite strain (deviatoric epsilon) of model after 0.7 Myr .. 138
Figure 6.7 The view of finite strain (deviatoric epsilon) after 1.1 Myr ................. 138
Figure 6.8 The view of the profile length of the numerical model ........................ 140
Figure 6.9 The initial view of the model. ............................................................... 140
Figure 6.10 The topographic cross-section of the study area ................................... 141
Figure 6.11 Crust-mantle interface values ............................................................... 141
Figure 6.12 The temperature distributions on model after 5 Myr for 200K-500K .. 142
Figure 6.13 The finite strain field on model after 5 My for 200ºK-500ºK .............. 142
Figure 6.14 a) The velocity fields on model after 5 Myr for 200ºK-500ºK ............. 143
Figure 6.14 b) The velocity field with vectors on model after 5 Myr ..................... 143
Figure 6.15 The temperature distributions on model after 10 Myr for 200K-500K 144
Figure 6.16 The finite strain field on model after 10 My for 200ºK-500ºK ............ 144
Figure 6.17 a) The velocity fields on model after 10 Myr for 200ºK-500ºK ........... 145
Figure 6.17b) The velocity fields with vectors on model after 10 Myr for 200ºK-
500ºK ..................................................................................................... 145
Figure 6.18 The temperature distributions on model after 15 Myr for 200ºK-500ºK
............................................................................................................... 146
Figure 6.19 The finite strain fields on model after 15 Myr for 200ºK-500ºK ......... 146
Figure 6.20 a) The velocity fields on model after 15 Myr for 200ºK-500ºK ........... 147
Figure 6.20b) The velocity fields with vectors on model after 15 Myr for 200ºK-
500ºK ..................................................................................................... 147
Figure 6.21 The temperature distributions on model after 5 Myr for 273K-773K .. 148
Figure 6.22 The finite strain fields on model after 5 Myr for 273ºK-773ºK ........... 148
Figure 6.23 a) The velocity fields on model after 5 Myr for 273ºK-773ºK ............. 149
Figure 6.23b) The velocity fields with vectors on model after 5 Myr for 273ºK-
773ºK .................................................................................................... 149
Figure 6.24 The temperature distributions on model after 5 Myr for 273ºK-900ºK 150
Figure 6.25 The finite strain fields on model after 5 Myr for 273ºK-900ºK ........... 150
Figure 6.26 a) The velocity fields on model after 5 Myr for 273ºK-900ºK ............. 151
Figure 6.26b) The velocity fields with vectors on model after 5 Myr for 273ºK-
900ºK ..................................................................................................... 151
Figure 6.27 Temperature distributions on model after 5 Myr for 273ºK-1400ºK ... 152
xvii
Figure 6.28 The finite strain fields on model after 5 Myr for 273ºK-1400ºK ......... 152
Figure 6.29 a) The velocity fields on model after 5 Myr for 273ºK-1400ºK ........... 153
Figure 6.29 b) The velocity fields with vectors on model after 5 Myr for 273ºK-
1400ºK ................................................................................................... 153
Figure 6.30 The finite strain fields on model after 5 Myr for 273ºK-900ºK with 0.125
Pa ........................................................................................................... 154
Figure 6.31The velocity fields on model after 5 Myr for 273ºK-900ºK with 0.e125
Pa ........................................................................................................... 154
xviii
LIST OF TABLES
Page
Table 3.1 The coordinates and observation days of the stations ................................ 34
Table 3.2 The coordinates and observation days of the General Command of
Mapping Stations ....................................................................................... 35
Table 3.3 The Coordinates of IGS stations which used in the processing ................. 35
Table 3.4 Horizontal GPS velocities of TURDEP and CORS-TR projects stations in
a Eurasian fixed frame and 1-σ uncertainties ............................................ 67
Table 3.5 Horizontal GPS velocities of General command Mapping stations in a
Eurasian fixed frame and 1-σ uncertainties ............................................... 68
Table 3.6 Euler Vectors Relative to Eurasia .............................................................. 72
Table 4.1 Horizontal GPS velocities of study area sites in a Eurasian fixed frame and
1-σ uncertainties ......................................................................................... 90
Table 4.2 Correlation coefficients of GPS and gravity observation results ............... 94
Table 6.1 Physical parameters used in the numerical modeling .............................. 139
xix
CHAPTER ONE
INTRODUCTION
Western Anatolia is one of the most seismically active and rapidly extending
regions in the world and is currently experiencing an approximately N–S continental
extension since at least Miocene time (Şengör et al., 1985; Yılmaz et al., 2000). Due
to this important case of Western Anatolia, deformations of the region were
examined by GPS and gravity measurement in this study.
Firstly, in the second chapter, the geological settings of the study area were given
briefly. In the application sections, in chapter three, the basic information of Global
Positioning System and data processing steps of GAMIT/GLOBK software were
explained. The GPS stations of TURDEP project, CORS-TR project and General
Command of Military were processed by using GAMIT/GLOBK software relative to
Eurasia fixed frame. The velocities of the stations were found as approximately 20-
25 mm/year to SW direction and the solution was compared with the previous study
of McClusky et al. (2000) and the results of TUBITAK project No:108Y285. Due to
the differences on the velocity directions, the study was separated to four regions.
Additionally, for determining the regional deformation, by using Euler vectors, the
Aegean and Anatolian block fixed solutions were presented. In Anatolian block
solutions, the area was separated into 3 groups according to the velocities of the
stations and the magnitude of the velocities was found as approximately 3-15 mm/yr.
Finally, the GPS solutions; Eurasia fixed frame, Anatolian and Aegean block fixed
solutions were compared with each other.
In chapter four, the GPS and microgravity data, which were obtained
simultaneously at 6 points; Akhisar (Manisa), Eşme (Uşak), Çal (Denizli), Bademli
(İzmir), Borlu (Manisa), Karacasu (Aydın), were compared for discussing about
vertical mass changes on the measurement points. For this purpose, the correlation
coefficients between these data set were calculated. The earthquakes distributions
which occurred between the years 2005-2014 and topographic changes were
1
compared together for interpreting the vertical changes on these points with the
relations between the GPS and microgravity.
In chapter five, obtained GPS velocities by using Gamit/ Globk software were
compared with the modeled GPS velocities by Coulomb 3.3 software on the northern
normal fault of Gediz graben and southern normal fault of the Büyük Menderes
graben by using Coulomb 3.3 software. In Gediz Graben application, the modeled
and observed GPS velocities are fitted at AKHT (Akhisar), BORT (Borlu) and
TRGT (Turgutlu). But there is not compliance between the velocities for SALH
(Salihli). Additionally, Coulomb software can not model velocities for ESMT and
CALT stations due to their far away locations from the fault. Then, the coulomb
stress changes were calculated and plotted for the depths of 4 km and 6 km and
additionally for the depth range between 0-4 km and 0-6 km. In Büyük Menderes
graben application, the modeled and observed GPS velocities are fitted for KRPT
and KRCT. The coherence between the modeled and observed velocities for CALT
is not well. Additionally, the modeled and observed velocities of BDMT have same
directions and they are fitted but the magnitude of the modeled velocity is higher
than the observed one. By these parameters the coulomb stress changes were
calculated and plotted for the depths of 3 km and 5 km and additionally for the depth
range between 0-3 km and 0-5 km. Additionally, the coulomb stress changes were
compared with the earthquakes occurred at the region between the years 1970-2014.
Complex structures systems are often too complicated to simply derive
relationships between applied loads and internal stresses. Hence, large structures are
divided up into many individual finite elements; that have a much simpler structural
form. The relationship between load, displacement, stresses and strains in a finite
element can be determined. Thus, it is computationally possible for a complex
structure to be modelled by assembling many individual finite elements. The
assembling process must satisfy equilibrium and continuity (Chandrupatla &
Belegundu, 2002). By this idea, in the last chapter (chapter six), the finite element
software ADELI was used for modeling deformation of Western Anatolia. The south
border of Menderes Extensional Metamorphic Complex (MEMC) at south side and
the North Anatolian Fault zone at north side were chosen as the boundary conditions
2
of the model. To the initial model, 3 mm/yr velocity magnitude was given to the
borders for giving extension to the model. The strain and velocity fields after 5Myr,
10Myr and 15 Myr of deformation were obtained. Finally, the findings were
compared with the topography and bottom topographic map for investigating the
crustal extension.
3
CHAPTER TWO
GEOLOGY OF THE STUDY AREA
Western Anatolia is one of the most seismically active and rapidly extending
regions in the world (Dewey & Şengör, 1979; Şengör & Yılmaz, 1981; Jackson &
McKenzie, 1984; Şengör et al., 1985; Eyidoğan & Jackson, 1985; Şengör, 1987;
Seyitoğlu & Scott, 1992; Bozkurt, 2001). It has continental extension approximately
N–S direction with the rate of 30-40 mm/year (Oral et al., 1995; Le Pichon et al.,
1995, McClusky et al., 2000). Western Anatolia is the part of the ‘Aegean
Extensional Province’ which is the region of distributed extension (Bozkurt, 2001)
(Figure 2.1).
Figure 2.1 Simplified tectonic map of Turkey showing major neotectonic structures and neotectonic
provinces. Red square shows the study area (modified from Bozkurt 2001).
The Aegean Extensional Province has experienced several compressional and
extensional deformational phases which have been summarized in many papers
(Şengör & Yılmaz, 1981; Okay & Tüysüz, 1999; Ring et al., 2010; Rimmelé et al.,
2003; van Hinsbergen et al., 2005, 2010; Çemen et al., 2006 and Jolivet et al., 2013).
All researchers agree that the province has experienced a Cenozoic extensional
tectonics and it is still effective. On the other hand, the initial time of the Cenozoic
4
extension has been controversial. Many researchers recommended that the Cenozoic
extensional tectonics in the western Anatolian began in the Middle Miocene (Yılmaz
et al., 2000) or earliest Miocene (Seyitoğlu et al., 1992). Several recent studies,
however, suggested that the extension began in Late Oligocene in Western Anatolia
(Lips et al., 2001; Catlos & Çemen; 2005; Çemen et al., 2006), or in Early Eocene in
the Rhodope region (Jolivet & Brun, 2010) (Ersoy et al. ,2014).
The cause and origin of the Cenozoic extension has also been controversial. The
proposals fall into five different models:
(1) ‘Tectonic escape’ model: the westward extrusion of the Anatolian block
along its boundary structures since the late Serravalian (12 Ma) (Dewey & Şengör,
1979; Şengör, 1979, 1980, 1987; Şengör & Yılmaz, 1981; Şengör et al., 1985; Görür
et al., 1995; Çemen et al., 1999).
(2) ‘Back-arc spreading’ model: back-arc extension caused by the south–
southwestward migration of the Aegean Trench system. However, there is no
consensus on the inception date for the subduction roll-back process and proposals
range between 60 Ma and 5 Ma (McKenzie, 1978; Le Pichon & Angelier, 1981;
Jackson & McKenzie, 1988; Spakman et al., 1988; Meulenkamp et al., 1994; Jolivet
& Brun, 2010; Jolivet et al., 2013).
(3) ‘Orogenic collapse’ model: the extension is induced by the spreading and
thinning of over-thickened crust following the latest Paleocene collision across
Neotethys during the latest Oligocene–Early Miocene (Seyitoğlu & Scott,1992;
Seyitoğlu et al., 1992).
(4) A three-stage continuous simple shear extensional model as a result of the
'tectonic escape', 'back-arc spreading' and 'orogenic collapse' mechanisms (Çemen et
al., 2006; Gessner et al., 2013).
(5) ‘Episodic’: a two-stage graben model: that involves a Miocene–Early
Pliocene first stage (orogenic collapse), and a Plio-Quaternary second phase
(westward escape of the Anatolian block) of N–S extension (Sözbilir & Emre, 1996;
5
Koçyiğit et al., 1999; Bozkurt, 2000, 2001, 2003; Işık & Tekeli, 2001; Lips et al.,
2001; Sözbilir, 2001, 2002; Bozkurt &Sözbilir, 2004; Koçyiğit, 2005).
Western Anatolia is the most important part of the Aegean Extensional Province
which includes Menderes Extensional Metamorphic Complex (MEMC) (Bozkurt &
Park, 1994; Emre, 1996; Lips et al., 2001; Işık & Tekeli, 2001; Çemen et al., 2006).
MEMC is one largest metamorphic core complexes in the world and began to
develop during the Late Oligocene-Early Miocene extensional deformation (Bozkurt
& Park, 1994; Hetzel et al., 1995; Işık & Tekeli, 2001; Işık et al., 2004; Çemen et al.,
2006; Glodny & Hetzel, 2007) and occurred in poly-phase deformation (Ersoy et al.,
2014).
The MEMC is bounded by NE-SW trending Miocene strike-slip faults along its
eastern and western margins edges (Çemen et al., 2006; Sözbilir et al., 2011; Ersoy et
al., 2011). The NE-SW trending strike-slip faulting along the western side of the
MEMC is known as İzmir-Balıkesir Transfer Zone (İBTZ; Sözbilir et al., 2003;
Erkül et al., 2005; Kaya et al., 2007; Uzel & Sözbilir, 2008; Ersoy et al., 2011;
Gessner et al., 2013). Several Miocene to Recent transtensional areas and basins
were developed along this zone. The eastern side of MEMC is bounded by the NE-
SW trending Southwestern Anatolian Shear Zone (Çemen et al., 2006; Karaoğlu &
Helvacı, 2012) which includes lots of oblique-slip faults and associated extensional
basins (Ersoy et al., 2014).
It has been proposed that the Cenozoic extensional tectonics in the Aegean was
begun as early as in Eocene (~45 Ma) by slab-roll back processes (Dinter & Royden,
1993; Brun & Faccenna, 2008; Brun & Sokoutis, 2012). The Cenozoic extensional
tectonics and related core complex formation migrated to the south with time, and
during the Late Oligocene to Middle Miocene times, Kazdağ, Cycladic and
Menderes Extensional Core Complexes formed (Ersoy et al., 2014).
The northern side of the MEMC was formed in three main stages: (1) latest
Oligocene-Early Miocene detachment faulting along the Simav Detachment Fault
(Işık & Tekeli, 2001; Isik, et al., 2003), (2) Middle Miocene detachment faulting
along Gediz (Alaşehir) Detachment Fault (Emre, 1996; Seyitoğlu et al., 2002) and
6
Büyük Menderes Detachment Fault (Bozkurt, 2000; Çemen et al., 2006; Gürer et al.,
2009), (3) Pliocene-Quaternary high-angle normal faulting, cutting the older
structures throughout the western Anatolia (Yılmaz et al., 2000). Each of these stages
is responsible for deformation, basin formation, sedimentation and extensive
volcanic activity in the upper plate (Ersoy et al., 2014).
By the radiometric age determination studies, it was supported that the first stage
Cenozoic extensional deformation in the northern MECM, along the Simav
Detachment Fault, has begun during the Late Oligocene. Several supra-detachment
basins in the upper plate, such as Demirci, Selendi and Uşak-Güre basins are located
in the northern MECM (Purvis et al., 2005; Çemen et al., 2006; Ersoy et al., 2011).
On the other hand, there is no supradetachment basin in the southern MEMC. It
means that the first-stage exhumation of the MEMC was occurred asymmetrically.
The second stage of the Cenozoic extension in the MEMC occurred in its central
parts, along the north-dipping Gediz (Alaşehir) Detachment Fault and south-dipping
Büyük Menderes Detachment Fault. These faults have also controlled the basins in
the upper plate (Sözbilir, 2002; Çemen et al., 2006; Çiftçi & Bozkurt, 2009; Şen &
Seyitoğlu, 2009; Öner & Dilek, 2013). The episodic forming of the MEMC was
accompanied also by Miocene to Recent NE-SW-trending strike-slip faulting along
its western margin (Ersoy et al., 2011) known as the IBTZ (Sözbilir et al., 2003;
Erkül et al., 2005; Uzel and Sözbilir, 2008; Ersoy et al., 2011; Uzel et al., 2013).
Complex deformation along the IBTZ is also resulted in basin formation and
volcanic activity (Ersoy et al., 2014).
7
CHAPTER THREE
DEFORMATION ESTIMATIONS WITH GPS PROCESSING
The Global Positioning System (GPS) is a satellite-based radio-navigation system
which is developed by the United States Department of Defense since early 1970s.
GPS was opened to civilian use in the 1980s. It is formed by a constellation of 24
satellites in six orbital planes with four satellites in each plane which are 20200 km
above the earth. The principal technique of GPS is to measure the time difference
between the satellite clock and the user’s receiver clock on the Earth and scale it by
speed of light in order to obtain the distance between the receiver and the satellite
observed. The approximate positions of the satellites are broadcasted along with the
GPS signal to the user via navigation messages (almanac and ephemerides).
Therefore, the position of the receiver can be determined by the known positions of
the satellites and the computed distances between the receiver and the satellites (Xu,
2007). On the other hand, a Global Navigation Satellite System (GNSS) is the name
covering all satellite positioning systems from different countries, namely, GPS
(USA), GLONASS (Russia), Galileo (European Union), Compass (China), QZSS
(Japan), IRNSS (India) and SBAS (Satellite Based Augmentation Systems) systems
(Kahveci & Yıldız, 2009).
The free global availability and accuracy of GPS signals for positioning and
timing, combined with the low cost of receiver chipsets, has made GPS the preferred
solution for a very wide and growing range of civilian applications (Locata, nd.)
Some civilian applications of GPS can be written as: surveying, geodesy, geophysics,
aviation, road transport, shipping & rail transport, meteorology, precision agriculture,
recreational activities, etc.
3.1 The Segments of GPS
GPS system consists of 3 segments which are Space, Control and user segments
(Figure 3.1).
8
Figure 3.1 GPS segments (Infohost, nd)
3.1.1 The Space Segment
The space segment consists of 24 satellites (currently 31 in November 2014),
nearly circular orbits about 20,200 km above the earth. The satellites are arranged in
6 orbital planes (Figure 3.2). Each plane is tilted at 55 degrees relative to the equator,
to provide polar coverage. Each satellite orbits the earth twice a day. Therefore, at
least four satellites are in view at any time, from any place on the earth’s surface.
This is significant because a GPS receiver requires signals from at least four satellites
in order to determine its location in three dimensions (3D). Each satellite contains
several atomic clocks to keep accurate time. Each satellite continuously broadcasts
low-power radio signals that identify it and provide information about its location in
space, as well as system timing and other data. Each GPS satellite transmits data on
three frequencies: L1 (1575.42 MHz), L2 (1227.60 MHz) and L5 (1176.45 MHz).
Pseudorandom noise (PRN) codes, along with satellite ephemerides, ionospheric
model, and satellite clock corrections are superimposed onto the carrier (Kahveci &
Yıldız, 2009).
9
The L1 and L2 carrier signals are modulated for receiving the information such as
satellite clock corrections, orbital parameters to the receiver by some codes and
navigation messages. In this modulation processing, unique meaningful PRN
(Pseudo Random Noise) code number are given to each satellite. The satellite signal
can be separated from each other by this unique PRN code (Montenbruck & Gill,
2000).
Figure 3.2 The space segment of GPS (Colorado University, nd)
At L1 frequency, there are two PRN codes and navigation message data. These
two codes are called as C/A (Course/Acquisition, Clear/Access) code and P
(Precise/Protected Code) codes. At L2 frequency, there are P code and navigation
message data. In the other words, the C/A code which is available for civil users is
transmitted with L1 frequency. P code which is available only for military is
transmitted both L1 and L2 frequency (Kahveci & Yıldız, 2009).
3.1.2 The Control Segment
The Control Segment consists of tracking stations system located around the
world (Figure 3.3). The Master Control station, located in Colorado, is responsible
10
for overall management of the remote monitoring and transmission sites. It measures
signals from the satellites and it calculates any position or clock errors for each
individual satellite based on information received from the monitor stations. The
corrected data are uploaded by the Master Control station. Finally, the satellites send
the new data over radio signals to the GPS receiver back to earth. The 4 Monitor
Stations located around the world (Hawaii and Kwajalein in the Pacific
Ocean; Diego Garcia in the Indian Ocean; Ascension Island in the Atlantic Ocean)
track up to 11 satellites twice a day (Environmental, nd).
Figure 3.3 The control segment of GPS (Environmental, nd).
3.1.3 The User Segment
The user segment consists of all civil and military GPS users. This segment
requires having an antenna and a receiver for decoding and storing the information
sent from the space segment.
3.2 Reference Coordinate Systems of GPS
In formulating the mathematics of satellite navigation information, it is necessary
to choose a reference coordinate system in which satellite and receiver can be
11
represented. In this formulation, it is typical to describe satellite and receiver states in
terms of position and velocity vectors measured in a Cartesian coordinate system
(Kaplan & Hegarty, 2006).
3.2.1 Earth-Centered Inertial (Space-fixed) (ECI) Coordinate System
For the purposes of measuring and determining the orbits of the GPS satellites, it
is convenient to use an Earth-centered inertial (ECI) coordinate system, in which the
origin is at the center of the mass of the Earth and whose axes are positing in fixed
directions with the respect to the stars.
In ECI coordinate system, the xy-plane is taken to coincide with the Earth's
equatorial plane, the x-axis is permanently fixed in a particular direction relative to
the celestial sphere, the z-axis is taken normal to the xy-plane in the direction of
North Pole, and the y-axis is chosen to form right-handed coordinate system (Kaplan
& Hegarty, 2006).
3.2.2 Earth-Centered Earth-Fixed (ECEF) Coordinate System
For the purpose of computing the position of a GPS receiver, it is more
convenient to use a coordinate-system that rotates with the Earth, known as an Earth-
centered Earth-fixed (ECEF) system. In such a coordinate system, it is easier to
compute the latitude, longitude and height parameters that the receiver displays. As
in ECI coordinate system, the ECEF coordinate systems' xy-plane is coincide with
the Earth's equatorial plane.
In the ECEF system, the x-axis points in the direction of 0° longitude, the y-axis
points in the direction of 90° E longitude and the z-axis is chosen to be normal to the
equatorial plane in the direction of the geographical North Pole. Therefore, the x, y,
and z-axes rotate with the Earth. The Cartesian coordinates (x, y, and z) of the user's
receiver are computed in ECEF system (Kaplan & Hegarty, 2006).
12
3.2.3 World Geodetic System-1984 (WGS-84)
The standard physical model of the Earth used for GPS applications is World
Geodetic System 1984 (WGS 84). This is the reference system used by U.S.
Department of Defense where has the responsibility of using the GPS system. WGS
84 provides an ellipsoidal model of the Earth's shape. In this model, cross-section of
Earth parallel to the equatorial plane are circular. The equatorial cross-section of the
Earth has radius 6,378.137 km, which is the mean equatorial radius of the Earth
(Kaplan & Hegarty, 2006).
3.3 Source of Errors
GPS system is the highest accurate global positioning and navigation system
although it has some weaknesses as in all other systems. In other words, some
random and systematic deviations are involved in the results of GPS measurements
(Kahveci & Yıldız, 2009). The main sources of errors which affect the distance
measurements between satellites and receivers are explained briefly.
3.3.1 Ephemeris (Orbital Position) Errors
Ephemeris errors are supposed to be a major factor limiting the usefulness
of GPS in high precision geodesy and applications. Even though the satellites
positions are constantly monitored, slight position or "ephemeris" errors can occur.
So, if the satellite location information in GPS navigation message has low accuracy,
this effect is called as ephemeris error. For removing the ephemeris errors, the
satellite orbits should be measured more sensitively by measuring or modeling the
forces acting on satellite with high accuracy (Kahveci & Yıldız, 2009).
3.3.2 Satellite and Receiver Clock Errors
Even though the GPS satellites are very sophisticated they contain some small
errors in the system. The atomic clocks used in GPS satellites are very precise but
13
they're not perfect. Small discrepancies can occur, and these cause measurement
errors in travel time. Since determining position is based on time measurements, the
greatest source of error is caused by satellite clock drift. These errors are monitored
and corrected by the Master Control Station. This effect can be removed by using
sensitive atomic clocks or using differential observations (Kahveci & Yıldız, 2009).
The role of the receiver and satellite clocks is very important in precise GPS
surveying. The receiver and satellite clock errors are multiplied by the speed of light.
Hence, because of the factor speed of light, a small clock error can cause a very large
code and phase error on the earth. For example a clock error of 1 µs translates to 300
m in range error. GPS receivers use cheap quartz crystal oscillators, to keep the cost
within a reasonable level. These oscillators have also the advantage of being small
devices and consume less power. In absolute positioning, the receiver clock offset
has to be estimated as an unknown parameter in the navigation solution which
estimates the receiver position and receiver clock at the same time. The receiver
clock offset can be estimated within 1 µs or better (Leick, 1995). In relative
positioning, between satellites differencing eliminates the receiver clock error term.
In Network RTK, where double difference is adopted as the main observable,
receiver and satellite clocks are completely eliminated through differencing.
3.3.3 Atmospheric Effects
The ionosphere and troposphere both refract the GPS signals. The ionosphere is
the ionized part of the earth’s atmosphere lying between about 50 km and several
earth radii (Davies, 1990). The amount of free electrons is more enough to change
the propagation of electromagnetic waves. The effects of ionosphere are different on
code and phase measurements. While the ionosphere effects as group delay on code
measurements, it effects as phase advance on phase measurements. Since the
ionospheric effect is frequency dependent, this effect can be removed by using dual-
frequency GPS receiver.
Troposphere is the lowest layer and the non-ionized part of the atmosphere. The
electromagnetic signals are affected by the neutral (non-ionized) atmosphere and this
14
effect is called tropospheric delay. Neutral atmosphere changes the speed and
directions of the electromagnetic waves. The tropospheric delay is frequency
independent and this effect can not be removed by using dual-frequency GPS
receiver. This effect can be decreased by using suitable modeling (Kahveci & Yıldız,
2009).
3.3.4 Selective Availability
Selective Availability (SA) is the intentional degradation (limits accuracy of
satellite signals) of the GPS system by the U.S. Department of Defense for security
reasons. On May 1, 2000 the White House announced a decision to discontinue the
intentional degradation of the GPS signals to the public beginning at midnight.
(Kahveci & Yıldız, 2009).
3.3.5 Multipath
Multipath is the signal refection effect which is occurred when the satellite signals
reach the receiver antenna by two or more paths. The possible sources of reflection
around the receiver antenna are buildings, vehicles, water surfaces (sea, lake, etc.)
and other reflective surfaces (Figure 3.4). If the antenna is kept stable at the same
point a few days, the main effect of antenna signal reflection can be measured.
Therefore, multipath error can be corrected by removing this effect (Kahveci &
Yıldız, 2009).
15
Figure 3.4 Sources of signal interference, multipath (Ashtray, nd).
3.3.6 Receiver Antenna Phase Center Error
The antenna phase center variation differs 1-2 mm up to 1-2 cm from each other
related with the type of antenna. The amount of antenna phase center variation is
different at each antenna type, so it is difficult to model them. Due to the same type
of antenna show similar variations, by directing the antennas to the same direction
(generally to magnetic north) this effect of error is minimized (Kahveci & Yıldız,
2009).
3.4 Differential Observations Based on GPS Measurements
The differences created by code and phase observation are used for correcting the
some sources of errors such as the receiver clock errors, satellite clock errors and
phase initial ambiguity.
3.4.1 Single Differences
The differences between the phase observations which are done simultaneously
by two different receivers respect to the same satellite are called single differences
observation. By this observation, satellite clock error is eliminated. If the single
16
difference observation is done for the single receiver between two satellites, in this
case, receiver clock error is eliminated.
3.4.2 Double Differences
The differences between the two single differences are called double differences
observation. By the double differences observation, both of the clock errors (satellite
and receiver) are removed.
3.4.3 Triple Differences
The differences between the two double differences observations on two receivers
are called triple differences. By triple differences observation, the initial phase
ambiguity is removed (Kahveci & Yıldız, 2009).
3.5 The Principle of GPS Measurement
GPS gives the exact position of any point on the earth by computing precisely
where each satellite is in space, measuring the travel time of radio signals broadcast
by the satellites, and accounting for delays the signals experience as they travel
through the earth’s atmosphere. Firstly, when a GNSS receiver is first turned on, it
downloads orbit information from all the satellites called an almanac. The almanac is
a data file that contains information of orbits and clock corrections of all satellites.
As the second step, the GNSS receiver calculates the distance from each satellite to
the receiver by using the distance formula (distance = velocity x time). The receiver
already knows the velocity, which is the speed of a radio wave or 300 km per second
(the speed of light). To determine the time part of the formula, the receiver times
how long it takes for a signal from the satellite to arrive at the receiver. The GNSS
receiver multiplies the velocity of the transmitted signal by the time it takes the
signal to reach the receiver to determine distance. Consequently, the receiver
determines position by using triangulation. When it receives signals from at least
three satellites the receiver should be able to calculate its approximate position (a 2D
17
position). The receiver needs at least four or more satellites to calculate a more
accurate 3D position. The position can be reported in latitude/longitude, UTM, or
other coordinate system (Nwcg, nd).
Several classifications can be made for GNSS positioning methods. But, there are
mainly two types of positioning methods, namely, absolute and relative positioning.
(Kahveci et al., 2013). A general classification of GNSS positioning methods are
shown in Figure 3.5. In relative positioning, code (pseudorange) and phase (carrier
beat phase) measurements are observed. Code (pseudorange) measurements are
observed for obtaining navigation in real-time applications. In the applications which
need high accuracy and in high precision scientific studies, phase observations are
used (Kahveci & Yıldız, 2009). Therefore, in this study relative static positioning
with phase observations method was used and only the principle of phase
measurement was explained.
Since 1980s until 2000s episodic GPS campaigns with several hours of static
relative phase observations depending on the baseline lengths were widely in use for
scientific studies and researches. Because performing long observation times (from
several hours to 24 hours) was the only way to solve for all unknowns and eliminate
some error sources on GPS baselines. But with the advent of Continuously Operating
Reference Stations (CORS) networks, it is now a usual and economic procedure to
obtain and process necessary GPS/GNSS data continuously and in real time. The
name of such a network in Turkey is CORS-TR and it has been in use since 2009.
18
Figure 3.5 General classifications of GNSS Positioning methods (Kahveci et al., 2013).
3.5.1 The Principle of Phase Measurement
This method achieves only millimeter accuracy on baselines of several
hundred kilometers, so it is used for tectonic movement measurements. The
measurement is made on the carrier phases L1 and L2 with wavelengths of 19
cm and 24.4 cm, respectively. The observation consists of the phase
difference between the signal received from the satellite and generated by the
receiver. It can be written for satellite i and the station j.
Φ𝑖,𝑗(𝑡) = Φ𝑟𝑒𝑐,𝑖,𝑗(𝑡) −Φ𝑔𝑒𝑛,𝑖,𝑗(𝑡) (3.1)
This phase is ambiguous, it is determined with the top part of fractional number
of waves between the satellite and the station cycles (Figure 3.6). The
oscillation between the signal received from the satellite and the output from
the receiver is not measurable as the difference between the satellite clock and
receiver reference time t0. The measurable part of the period is ∆t in Figure 3.6. The
19
observation may be converted into units of cycles by multiplying fo which has the
fundamental frequency, 10.23 MHz At time t1, beginning of the measurement, the
effective observable part, Φ𝑖,𝑗′ :
Then the fractional part of the cycle between the received signal and generated by receiver:
Φ𝑖,𝑗′ (𝑡1) = −Δ𝑡(𝑡1) ∙ 𝑓𝑜 (3.2)
While the measurement is taken in a certain time, the distance between the
satellite and the station varies during the recording. Therefore, the observable Φ𝑖,𝑗′
evolve over the time because of the geometric delay. The phase ambiguity, n, and
initial offsets,∆Φ(𝑡0) , remain constant. The continuous observation of ∆t only
provides information on the evolution of the distance between the satellite and the
receiver. The desired amount remains, however the signal propagation time between
the satellite and the receiver, it corresponds to the geometric delay τ of Figure 3.6.
The relationship between the geometric delay, the observable and the unknown
parameters are given by King et al. (1985). The geometric delay 𝜏𝑖,𝑗 which links the
signal emitted by the satellite i to the j received by the receiver is:
Φ𝑟𝑒𝑐,𝑖,𝑗(𝑡1) = Φ𝑒𝑚,𝑖(𝑡1 − 𝜏𝑖,𝑗(𝑡1)) (3.3)
Here, Φ𝑟𝑒𝑐,𝑖,𝑗(𝑡) is the phase emitted by the satellite at 𝑡1 time, Φ𝑒𝑚,𝑖(𝑡) is the
phase emitted by the satellite at 𝑡1 − 𝜏𝑖,𝑗(𝑡1) time. With a value of approximately
0.1 second, τ is a small variation of the t time of the measurement. Therefore, it is
possible to carry out a limited development of Φ𝑒𝑚(𝑡 − 𝜏) around Φ𝑒𝑚(𝑡):
Φ(𝑡 − 𝜏) = Φ𝑒𝑚(𝑡) −Φ𝑒𝑚′ (𝑡) ∙ 𝜏(𝑡) + Φ𝑒𝑚
′′ (𝑡)2
∙ 𝜏2(𝑡) − … (3.4)
20
A development up to the second order in τ is sufficient, and the terms in τ2 are
negligible. In the simple case of a constant frequency 𝑓𝑜 of the satellite clock, the
phase emitted is written by:
Φ𝑒𝑚(𝑡) = ∫ 𝑓0𝑑𝑡 + Φ𝑒𝑚(𝑡𝑜𝑡𝑡0
) =𝑓0 ∙ (𝑡 − 𝑡0) + Φ𝑒𝑚(𝑡0) (3.5)
and its temporal derivative;
Φ𝑒𝑚′ (𝑡) = 𝑓0
Φ𝑒𝑚′′ (𝑡) = 0
are given. Here 𝑡0 is the beginning of the integration and it is the reference time or
phase emitted has a value of Φ𝑒𝑚(𝑡0). This value is considered as a constant of
integration in Equation 3.5.
By replacing Φ𝑒𝑚 and its temporal derivatives in the Equation 3.4 by the values
previously calculated in Equation 3.5, it is obtained;
Φ𝑒𝑚(𝑡 − 𝜏) = 𝑓0 ∙ (𝑡 − 𝑡0) + Φ𝑒𝑚(𝑡0) − 𝑓0 ∙ 𝜏(𝑡) (3.6)
At the t1 time of measurement and in the case of a stable frequency of the satellite
clock, were taken from the Equation 3.3 and Equation 3.6, the phase received by the
station is:
Φ𝑟𝑒𝑐,𝑖,𝑗(𝑡1) = 𝑓0 ∙ (𝑡1 − 𝑡0) + Φ𝑒𝑚,𝑖(𝑡0) − 𝑓0 ∙ 𝜏𝑖,𝑗(𝑡1) (3.7)
21
Figure 3.6 Principle of GPS phase measurement. When powering up the receiver at the time t0 , it
generates a signal Φgen similar with the signal transmitted by the satellite Φem .The frequency fo of
both signals is considered as constant. At t0 time, the phases have an offset ∆Φ(𝑡0). At t0 time, the
signal arrives from satellite to the receiver with a delay, τ. This moment 𝑡𝑜 + 𝜏 = 𝑡1 is considered as
the beginning of the measurement Φ = Φ𝑟𝑒𝑐 − Φ𝑔𝑒𝑛. If the fraction of the cycle (∆t) can be measured
accurately, the integer part of the cycle or ambiguity of the measure (n) becomes unknown. The
offsets of initial phases (ΔΦ(t0)) are also unknown. The geometric delay τ that it is wanted to
measured is therefore composed of
Δ𝑡 + 𝑛𝑓0
+ ΔΦ(𝑡0)𝑓0
whose only Δt is measurable (Vernant, 2003).
By assuming that the receiver clock is stable (like as satellite clock is stable) and
the frequency f0 is identical to the satellite, then the phase generated is expressed as:
Φ𝑔𝑒𝑛,𝑗(𝑡1) = ∫ 𝑓0𝑑𝑡 + Φ𝑔𝑒𝑛,𝑗(𝑡𝑜
𝑡1𝑡0
) =𝑓0 ∙ (𝑡1 − 𝑡0) + Φ𝑔𝑒𝑛,𝑗(𝑡0) (3.8)
As given previously, Φ𝑔𝑒𝑛,𝑗(𝑡𝑜) is the phase value generated at the beginning
time, 𝑡0, of the integration. This value becomes the integration constant.
At the time, t1, (which may be the beginning of the measurement), found for the
difference between the phase received (Equation 3.7) and the phase generated
(Equation 3.8) by the station is written;
22
Φ𝑟𝑒𝑐,𝑖,𝑗(𝑡1) −Φ𝑔𝑒𝑛,𝑗(𝑡1) = −𝑓0 ∙ 𝜏𝑖,𝑗(𝑡1) + Φ𝑒𝑚,𝑖,𝑗(𝑡0) − Φ𝑔𝑒𝑛,𝑗(𝑡𝑜) (3.9)
𝑓0 ∙ 𝜏𝑖,𝑗(𝑡1) corresponds to the geometric delay (Figure 3.6) is expressed in cycles.
Once the offset of the phases at reference the time subtracted from this period
Φ𝑒𝑚,𝑖(𝑡0) − Φ𝑔𝑒𝑛(𝑡0), therefore, the path is accessed between the satellite and the
station in the form of a decimal number of cycles. This value can be decomposed
into a number n integer and fractional part of cycles ∆t. When the measurement at
time t1, the observable is only the fractional part of the difference between the phase
received and the generated.
The geometric delay 𝜏 is the sum of three terms:
1. The fractional part of measurable cycle without ambiguity,
2. The integer number n of cycles of the signal between the satellite and the
station,
3. The part ΔΦ(𝑡0) =Φ𝑒𝑚,𝑖(𝑡0) − Φ𝑔𝑒𝑛(𝑡0) caused by the offsets of the satellite
phases and the receiver at the time of reference 𝑡0.
Therefore τ can be written as:
𝜏(𝑡1) = ∆Φ(𝑡0)𝑓0
+ Δ𝑡 + 𝑛𝑓0
(3.10)
The right side of Equation 3.9 is written as;
−𝑓0 ∙ 𝜏𝑖,𝑗(𝑡0) + Φ𝑒𝑚,𝑖,𝑗(𝑡0) −Φ𝑔𝑒𝑛,𝑗(𝑡0) = −𝑓0 ∙ Δ𝑡 − 𝑛 (3.11)
For the observable Φ𝑖,𝑗′ = −𝑓0 ∙ Δ𝑡 so it is given like:
Φ𝑖,𝑗′ (𝑡1) = −𝑓0 ∙ 𝜏𝑖,𝑗(𝑡1) + Φ𝑒𝑚,𝑖,𝑗(𝑡0) −Φ𝑔𝑒𝑛,𝑗(𝑡0) + 𝑛𝑖,𝑗 (3.12)
Equation 3.10 is the measurable part of Equation 3.1 at a given moment. By
23
knowing the ambiguity n and the value of the initial offset phasesΔΦ(𝑡0), 𝜏𝑖,𝑗 and
therefore the station-satellite distance is precisely determined. The variable 𝜏𝑖,𝑗 is the
only time-dependent in Equation 3.9. Therefore, in the general case of continuous
recording and without knowledge of ambiguity, Φ𝑖,𝑗(𝑡) shows only variations in
distance between the satellite and the receiver. The offset of the phases and the
ambiguity remain constant as long as the signal is not interrupted. After each loss of
signal, the ambiguity n of the phase measurement takes a new value. Continuous
observations during a certain time used to estimate by indirect methods, the values of
these parameters.
3.6 Data Processing Steps
3.6.1 Processing: The Three-Step Method
In this study GPS data is processed by using GAMIT/GLOBK software (Herring
et. al, 2010a, 2010b, King & Bock, 2009) which is created by three-step approach
described by Feigl et. al, (1993); Oral, (1994) and Dong et. al, (1998).
GAMIT/GLOBK is a comprehensive GPS analysis package developed at MIT,
the Harvard-Smithsonian Center for Astrophysics (CfA), and the Scripps Institution
of Oceanography (SIO) for estimating station coordinates and velocities, stochastic
or functional representations of post-seismic deformation, atmospheric delays,
satellite orbits, and Earth orientation parameters (Herring et al., 2010a).
In the first step, the weighted least squares algorithm are used to estimate the
relative positions of a set of stations, orbital and Earth-rotation parameters(EOPs),
zenith delays, and phase ambiguities by fitting to doubly differenced phase
observations and applying loose apriori constraints to all parameters (McClusky et. al,
2000). This process includes 3 or 4 International GNSS System (IGS) stations for
linking the regional networks with global networks. These calculations are performed
by GAMIT (King & Bock, 2009) part of the software. GAMIT produces estimations
and an associated covariance matrix ("quasi-observations") of station positions and
24
orbital and Earth-rotation parameters which are then used as the input files at second
step (GLOBK part).
In the second step, the loosely constrained estimates of station coordinates, orbits
and EOPs and their daily covariance are used as quasi-observations in a Kalman
filter for estimating a consistent set of coordinates and velocities. Then, for each day
the quasi-observations from the regional (local) analysis combined with the quasi-
observations of a global analysis of IGS data performed by SOPAC (McClusky et al.,
2000). These calculations are done by GLOBK part.
Kalman filter which is used in various branches of engineering (Cannon et al.,
1986, Schwards et al., 1989, Donellan et al., 1993, Feigel et al., 1993, Lu &
Lachapelle, 1994), becomes a method used in deformation analysis (Pelzer, 1986;
Çelik, 1998). By this method, the parameters (constant disruptive acceleration and
system noises) which are related to period and explained as stochastic can be solved
with modeling and especially the rapid changes on the point can be modeled (Demir,
1999). Additionally, even if the measurement quantities are less than the parameter
amounts, movement parameters can be estimated by the stochastic model which is
chosen by Kalman filter. It can be said that if the suitable stochastic model is created
for the linear or non-linear changes, the Kalman filter method can be affected on
determining the deformation (Ünver, 1994; Doğan, 2002).
In the third step, the reference frame for the velocity estimates are defined and
this frame is constrained on each day using a reliable set of global IGS stations with
realization of ITRF (International Terrestrial Reference Frame) no-net-rotation
(NNR) frame (Ray et al., 2004), while estimating the translation, orientation and
scale parameters for each day with the origin fixing module (glorg) of GLOBK part
of the software.
In parameter estimation based on least-squares, the conventional measure of
goodness-of-fit is the χ2 (chi-square) statistic, defined for uncorrelated data as the
sum of the squares of each observation residual (post-fit observed minus computed
observation, “o-c”) divided by its assigned uncertainty. In a GPS analysis parameter
correlations arise so the computation of χ2 in GAMIT or GLOBK involves a
25
complex matrix operation (see Dong et al., [1998]), but the idea is the same. The
value of χ2 is usually normalized by dividing by the “degrees of freedom” (df), the
number of observations minus the number of parameters estimated, so that the ideal
value for properly weighted, independent random observations is 1.0 (For details
Herring et al. (2010a) and Herring et al. (2010b) can be checked) .
3.6.2 Pre-Processing Steps
Before beginning the process in GAMIT/GLOBK software, there are some files
needed to prepare.
First of all it is needed to create an experiment directory (with the name of
processing year, as an example 2009) with two subdirectories: ‘tables’ and ‘Rinex’.
The session day files (Rinex files) of the IGS stations (which are downloaded from
http://sopac.ucsd.edu/dataArchive/dataBrowser.html) and study field local GPS
stations which are planned to use in processing must be copied into the "Rinex"
directory
Then, under the experiment directory (e.g. 2012), with running "sh_setup"
command:
sh_setup -yr 2012
all of the required templates and tables are linked and copied to "tables" subdirectory
automatically. "tables" directory contains lost of the files, but some of them are
needed to prepare before processing.
At below the needed changes on the files are described briefly. (The details can be
found at Herring et al. (2010a)). These are:
1. Process.defaults : In this file, only change is needed on ITRF (International
Referance Frame) version (ITRF2000, ITRF2005 or ITRF2008).
2. Sittbl. : In this file, it is need to write the confidence interval of GPS stations.
This file contains the confidence interval of IGS stations but it is needed to
26
add the GPS stations of the study area. If the coordinates of GPS stations are
confident, “NNN 0.005 0.005 0.01” is written after the name and code of
station such as:
IZMT IZMT_GPS NNN 0.005 0.005 0.01
3. Sites.defaults : This file contains the information about which local and IGS stations are to be used and how station data are to be handled. izmt_gps tusa localrx xstinfo glrepu
Here "izmt_gps" is the station code; "tusa" is the 4 lettered name of the data
group. "localrx" means that the information of the stations are not obtained
from ftp, this information will be obtained from the "station.info" file which
is prepared by the user. "glrepu" means stations will be used in GLRED
repeatability solutions
4. Station.info: This file is the most important file of the program. It must be
prepared very carefully. It contains general information of the stations (start
and finish time of the session, Antenna height, Antenna type, Height
measurement code, receiver type, hardware and software versions, Serial
numbers of receiver and Antenna)
5. Sestbl. : This file has the information about the files using during the
processing. The changes can be done on 'mapping function' type and 'ocean
tide loading', 'atmospheric loading'.
After preparing these files, the GPS data are ready for processing.
3.6.3 Processing Steps
3.6.3.1 Processing Steps of GAMIT Program
For starting the process on GAMIT program, "sh_gamit" command should be run.
The full command is:
sh_gamit -expt [4 lettered name of the data group] –s [year] [start day of session]
[final day of session] -orbit IGSF –yrext
27
or
sh_gamit –d [year] [1st day 2nd day.....final day of the session] -expt [4 lettered
name of the data group] -orbit IGSF –yrext
After "-s" command, the start day and final day of the session are written. As an
example; by writing " -s 2012 180 185 " the program process all days between 180
and 185th days of year of 2012. The days are given in Julian days.
If "-d" command is written, all processing days must be added. As an example;
" -d 2012 180 181 182 183 184 185 "
After "–expt" command 4 lettered data group name is written. The name must be
same which is written in "sites.defaults" file.
After "-orbit" the orbit files is specified. Here, IGSF (IGS Final Orbits) is chosen.
There are different options for orbit files.
By writing "–yrext" command the session day files are created like as 2012_180,
2012_181...etc.
Consequently, the outputs are downloaded and created at the session day files
(exp. 2012_180, 2012_181,etc.).
3.6.3.2 Processing Steps of GLOBK Program
GLOBK, is a global Kalman filtering program and it combines the geodetic
results which are created by GAMIT pogram. Besides, GLOBK is combined the
results which are created by other GPS processing program (e.g. Bernese, GIPSY)
successfully.
The main applications are succeed by GLOBK are given such as:
1) Combining analysis: It evaluates the position and orbital results which obtained by
GPS networks with daily GPS data.
28
2) Repeatability Analysis: It creates time-series of the daily GPS data
3) Velocity Analysis: It combines the daily data for creating velocity estimations.
Before beginning these processing steps, a file namely, ‘gsoln’ is created and all
of the steps are run under this file. At the day directories obtained by GAMIT have h-
files which contain daily solutions files from analysis of primary observations of the
stations. These h-files must be converted to binary h-files for using in Kalman filter
as the input files. This converting can be succeed by ‘htoglb’ command. ;
htoglb ../glbf ../glbf/svt f=NAME ../2012*/hNAME*
Here, ‘NAME’ is the 4 lettered name of the data group, 2012* presents the day
directories of year of 2012. Now, h-files can be used for combining solutions and all
daily h-files are copied to ‘glbf’ file.
For combining solutions, all h-files are needed to be in a single file as a list. For
collecting these h-files,
ls ../glbf/*.glx > NAME.gdl
command is used. Therefore, all h-files are collected in the same file as a list namely
NAME (4 lettered name of the data group).
For viewing the day solutions, the repeatabilities files are created by ‘glred’
command. For this purpose ‘glorg’ (glorg.cmd) and ‘globk’ (globk.cmd) command
files should be prepared carefully (for understanding how to prepare these files,
Herring et al. (2010a) can be checked).
glred 6 NAME_R01.prt NAME_R01.log NAME.gdl globk.cmd
ensum 2 su NAME _R01.ens va NAME _R01.ens NAME _R01.org
By these commands repeatability files (time-series) are created. For plotting the
time-series files,
29
multibase ../vaNAME_R01.ens –y
sh_base1c3n –year –o 1 –f mb*
commands are used. By these time-series files, the displacements can be obtained as
days or years.
For plotting the velocity vectors, ‘globk’ command is runned;
globk 6 NAME.prt NAME. log NAME.gdl globk.cmd
by this command, .prt and .log files are created by using .gdl file. For creating local
apriori (.apr) file for the study stations and getting position information of the
stations “sh_exglk” command is used:
sh_exglk –f NAME.org -apr NAME.apr –pos NAME.pos
The new created apriori file (NAME.apr) which contain the coordinates of the study
stations are added to globk.cmd file. Then, these command (globk and sh_exglk) are
rerun. Finally for plotting the velocities of the stations;
sh_plotvel –f NAME.pos –color –arrow_label mm –ps NAME -
RX1/X2/Y1/Y2
command is run. This command is to plot the figures on GMT (Generic Mapping
Tools). After –ps command, it is needed to write the name of the plotting file. After
“-R”, the coordinates of the plotting area need to given.
3.7 The Applications
The GPS stations which are located at Western Anatolia were chosen for
investigating the extension of the area. For this purpose, the stations of "Multi-
Disciplinary Earthquake Researches in High Risk Regions of Turkey Representing
Different Tectonic Regimes" (TURDEP) Project were reached from The Scientific
and Technological Research Council of Turkey (TUBITAK), Marmara Research
Center, Earth and Marine Science Institute and the stations of “Continuously
Operating Reference Stations-Turkey” (CORS-TR) project were provided from
30
General Directorate of Land Registry and Cadastre, Map Department and
additionally, the other GPS stations data were attained from General Command of
Mapping (Figure 3.7).
As the first step, the 11 continuous GPS stations of CORS-TR projects; AYD1
(Aydın, City Center), BALK (Balıkesir, City Center), CESM (Çeşme, Izmir), DEIR
(Demirci, Manisa), DENI (Denizli, City Center), HARC (Harmancık, Bursa), IZMI
(Izmir, City Center), KIKA (Kırkağaç, Manisa), MUGL (Muğla, City Center), SALH
(Salihli, Manisa), USAK (Uşak, City Center) and 10 continuous GPS stations of
TURDEP Project; AKHT (Akhisar, Manisa), BDMT (Bademli, Izmir), BORT (Borlu,
Manisa), CALT (Çal, Denizli), ESMT (Eşme, Uşak), IZMT (Izmir, City Center),
KRCT (Karacasu, Aydin), KRPT (Karpuzlu, Aydin), TRBT (Torbali, Izmir) and
TRGT (Turgutlu, Manisa) (Figure 3.8) were processed together by using
GAMIT/GLOBK for the days between 180th – 195th (as Julian days) of 2009-2010-
2011 years. The coordinates of the stations are given at Table 3.1.
As the second step, the stations of General Command of Mapping were processed.
In Figure 3.7, it is seen that there are 17 stations of General Command of Mapping
which shown by blue marks. But in the processing, the statistical (weighted root
mean square (wrms)) solutions were found too high. Therefore, 10 stations were
removed from the processing. Consequently, 7 stations; BAYO (Bağyolu, Manisa),
CEIL (Çeşme, Izmir), CKOY (Çiftlikköy, Izmir), EMET (Emet, Kütahya), LTFY
(Lütfiye, Bursa), YENF (Yenifoça, Izmir), ZEYT (Zeytinalan, Izmir) were processed
by using GAMIT/GLOBK for the days which was given at Table 3.2. Therefore, the
stations shown in Figure 3.8 were used in the processing.
31
Figure 3.7 The GPS stations are located Western Anatolia. Pink marks present TUBITAK/TURDEP
project station, yellow marks present CORS-TR project stations and blue marks present the stations of
General Command of Mapping. This figure is created by using Google-Map tool.
32
Figure 3.8 The GPS stations which used in the study are shown in general tectonic structures map of
Western Anatolia. Pink colored stations are the stations of TURDEP project, yellow colored are the
stations of CORS-TR project and blue colored are stations of General Command of Mapping
( Modified from Bozkurt, 2001).
33
Table 3.1 The coordinates and observation days of the stations.
Site Longitude (º) Latitude (º) Observation Days
STATIONS OF CORS-TR PROJECT
AYD1 27.83788 37.84073 2009-2011 / 180th-195th
BALK 27.89363 39.63937 2009-2011 / 180th-195th
CESM 26.37257 38.30382 2009-2011 / 180th-195th
DEIR 28.64840 39.03485 2009-2011 / 180th-195th
DENI 29.09213 37.76210 2009-2011 / 180th-195th
HARC 29.15276 39.67774 2009-2011 / 180th-195th
IZMI 27.08182 38.39481 2009-2011 / 180th-195th
KIKA 27.67221 39.10599 2009-2011 / 180th-195th
MUGL 28.36444 37.21636 2009-2011 / 180th-195th
SALH 28.12355 38.48309 2009-2011 / 180th-195th
USAK 29.40522 38.67921 2009-2011 / 180th-195th
STATIONS OF TURDEP PROJECT
AKHT 27.89513 38.99753 2009-2011 / 180th-195th
BDMT 28.04087 38.12027 2009-2011 / 180th-195th
BORT 28.55090 38.75191 2009-2011 / 180th-195th
CALT 29.40375 37.99182 2009-2011 / 180th-195th
ESMT 29.10617 38.42497 2009-2011 / 180th-195th
IZMT 27.19424 38.37510 2009-2011 / 180th-195th
KRCT 28.66741 37.82766 2009-2011 / 180th-195th
KRPT 27.81555 37.58215 2009-2011 / 180th-195th
TRBT 27.39112 38.31378 2009-2011 / 180th-195th
TRGT 27.90726 38.41491 2009-2011 / 180th-195th
34
Table 3.2 The coordinates and observation days of the General Command of Mapping Stations.
Site Longitude (º) Latitude (º) Observation Days
BAYO 27.30801 38.71103
2000 / 261th-262nd
2001 / 211th- 212nd
2005 / 123th -124th
CEIL 26.38529 38.31084 2000 / 271st – 272nd
2001 / 211st -212nd
CKOY 26.23337 38.28772 2001 /208th – 209th
2004 / 212nd -213rd
EMET 29.24559 39.33510 2000 / 271st – 272nd
2005 / 123th -124th
LTFY 28.41285 39.99288
2000 / 89th
2001 / 97th -297th
2004 / 157th -158th
YENF 26.79080 38.74109 2000 / 258th 259th
2001 / 214th -215th
ZEYT 26.49654 38.20466 2001/ 211th- 212nd
2004 / 215th -216th
Table 3.3 The Coordinates of IGS stations which used in the processing.
Site Longitude (º) Latitude (º)
TUBI 29.45068 40.78672 ISTA 29.01934 41.10445 BUCU 26.12574 44.46394 GLSV 30.49673 50.36418 NICO 33.39644 35.14099 MATE 16.70446 40.64913 MIKL 31.97284 46.97278 PENC 19.28153 47.78960 WTZR 12.87891 49.14420 ZECK 41.56506 43.78839
In order to define the station coordinates and velocities, 10 IGS stations of which
has a good processing and measurement history as well as which can be used to
calculate the velocity vectors were chosen to circulate the network area. For defining
Eurasia fixed reference frame; TUBI (Turkey), ISTA (Turkey), ZECK (Russia),
NICO (Cyprus), MIKL (Ukraine), GLSV (Ukraine), BUCU (Romania), PENC
35
(Hungary), WTZR (Germany) and MATE (Italy) were chosen as IGS stations
(Figure 3.9). For the processing of GPS observations, in addition to study area
stations, observations of 10 IGS stations were also included in order to make a link
between the local and global networks. The coordinates of the IGS stations were
given at Table 3.3. The GPS data were proceed by using ITRF 2008 (International
Terrestrial Reference Frame) relative to Eurasia fixed frame. The GAMIT/GLOBK
software was used to process the data by the steps which were explained previous
part. Firstly, with GAMIT day folders were created and then by GLOBK these daily
solutions were combined and processing solutions as time-series for TURDEP and
CORS- TR stations were plotted (Figure 3.10 up to Figure 3.29).
Figure 3.9 The IGS stations which used in processing are shown by red circle.
36
Figure 3.10 The processing solutions of AYD1 for the days between 180th-195th of the years between
2009-2011
37
Figure 3.11 The processing solutions of BALK for the days between 180th-195th of the years between
2009-2011
38
Figure 3.12 The processing solutions of CESM for the days between 180th-195th of the years between
2009-2011
39
Figure 3.13 The processing solutions of DEIR for the days between 180th-195th of the years between
2009-2011.
40
Figure 3.14 The processing solutions of DENI for the days between 180th-195th of the years between
2009-2011.
41
Figure 3.15 The processing solutions of HARC for the days between 180th-195th of the years between
2009-2011.
42
Figure 3.16 The processing solutions of IZMI for the days between 180th-195th of the years between
2009-2011.
43
Figure 3.17 The processing solutions of KIKA for the days between 180th-195th of the years between
2009-2011.
44
Figure 3.18 The processing solutions of MUGL for the days between 180th-195th of the years
between 2009-2011.
45
Figure 3.19 The processing solutions of SALH for the days between 180th-195th of the years between
2009-2011.
46
Figure 3.20 The processing solutions of USAK for the days between 180th-195th of the years between
2009-2011.
47
Figure 3.21 The processing solutions of AKHT for the days between 180th-195th of the years between
2009-2011.
48
Figure 3.22 The processing solutions of BDMT for the days between 180th-195th of the years
between 2009-2011.
49
Figure 3.23 The processing solutions of BORT for the days between 180th-195th of the years between
2009-2011.
50
Figure 3.24 The processing solutions of CALT for the days between 180th-195th of the years between
2009-2011.
51
Figure 3.25 The processing solutions of ESMT for the days between 180th-195th of the years between
2009-2010.
52
Figure 3.26 The processing solutions of IZMT for the days between 180th-195th of the years between
2009-2011.
53
Figure 3.27 The processing solutions of KRCT for the days between 180th-195th of the years between
2009-2011.
54
Figure 3.28 The processing solutions of KRPT for the days between 180th-195th of the years between
2009-2011.
55
Figure 3.29 The processing solutions of TRBT for the days between 180th-195th of the years between
2009-2011.
56
The wrms values (repeatabilities) give information about consistency among
observation days of the stations. For giving the clear information about the GPS
stations, the wrms repeatabilities were given as graphics (Figure 3.30 and 3.31). In
Figure 3.30, it can be seen that North, East and Up components of the stations are
below 10 mm which is the acceptable value in this study. Also, the wrms
repeatabilities of IGS stations are good for the processing days (180th- 195th days of
2009, 2010 and 2011) (Figure 3.31).
Figure 3.30 WRMS repeatabilities for North-East-Up directions from combination of TURDEP and
CORS-TR projects stations for 2009, 2010 and 2011.
0
2
4
6
8
AYD1
BALK
CESM DE
IRDE
NI
HARC
IZM
IKI
KAM
UGL
SALH
USA
KAK
HTBD
MT
BORT
CALT
ESM
TIZ
MT
KRCT
KRPT
TRBT
TRGT
Wrm
s (m
m)
Stations
N
E
U
57
Figure 3.31 WRMS repeatabilities for North (N)-East(E)-Up(U) directions from combination of IGS
for the days between 180th-195th of 2009, 2010 and 2011.
The same steps were done for stations of General Command of Mapping and
time-series were plotted (Figure 3.32 up to Figure 3.38).
0
2
4
6
8
10
12
TUBI ISTA BUCU GLSV MATE MIKL NICO PENC WTZR ZECK
Wrm
s (m
m)
Stations
N
E
U
58
Figure 3.32 The processing solutions of BAYO for 261st and 262nd days of 2000, 211st and 212nd days
of 2001, 123rd and 124th days of 2005.
59
Figure 3.33 The processing solutions of CEIL for 271st and 272nd days of 2000, 211st and 212nd days
of 2001.
60
Figure 3.34 The processing solutions of CKOY for 208th and 209th days of 2001, 212nd and 213rd days
of 2004.
61
Figure 3.35 The processing solutions of EMET for 271st and 272nd days of 2000, 123rd and 124th days
of 2005.
62
Figure 3.36 The processing solutions of LTFY for 89th day of 2000, 97th and 297th days of 2001 and
157th and 158th days of 2004.
63
Figure 3.37 The processing solutions of YENF for 258th and 259th days of 2000, 214th and 215th days
of 2001.
64
Figure 3.38 The processing solutions of ZEYT for 211st and 212nd days of 2001, 212nd and 213rddays
of 2004.
65
The wrms repeatabilities were given as graphics in Figure 3.39 and Figure 3.40.
In Figure 3.39, it can be seen that North, East and Up components of the stations are
below 10 mm except ZEYT. For ZEYT the value of Up component is near to 10 mm.
Also, the wrms repeatabilities of IGS stations seem good for the processing days
(Figure 3.40).
Figure 3.39 WRMS repeatabilities for North-East-Up directions from combination of General
Command of Mapping stations for 2000, 2001, 2004 and 2015.
Figure 3.40 WRMS repeatabilities for North-East-Up directions from combination of IGS stations for
2000, 2001, 2004 and 2015.
0
2
4
6
8
10
12
BAYO CEIL CKOY EMET LTFY YENF ZEYT
Wrm
s (m
m)
Stations
N
E
U
0
2
4
6
8
TUBI ISTA BUCU GLSV MATE MIKL NICO PENC WTZR ZECK
Wrm
s (m
m)
Stations
N
E
U
66
The velocities of the all stations with relative to Eurasia-fixed reference frame are
shown in Figure 3.41 and listed in Table 3.4 and Table 3.5. Generic Mapping Tools
(GMT) were used for presenting figures (Wessel & Smith, 1998). Table 3.4 Horizontal GPS velocities of TURDEP and CORS-TR projects stations in a Eurasian fixed
frame and 1-σ uncertainties (plotted with 95% confidence ellipses in Figure 3.41) (Here, σν E and σνN
are 1-σ uncertainties of E (east) and N (north) respectively, ρνEνN is correlation coefficient between E
(east) and N (north) uncertainties).
Site Longitude (º)
Latitude (º) νE (mm/year
)
νN (mm/year)
σνE (mm/year
)
σνN (mm/year
)
ρνEνN
STATIONS OF CORS-TR PROJECT AYD1 27.83788 37.84073 -17.40 -16.78 0.70 0.85 -0.022 BALK 27.89363 39.63937 -18.37 -6.54 0.36 0.49 -0.042 CESM 26.37257 38.30382 -16.46 -22.11 0.56 0.71 0.028 DEIR 28.64840 39.03485 -20.47 -8.07 0.40 0.54 -0.115 DENI 29.09213 37.76210 -18.03 -12.80 0.54 0.71 -0.109 HARC 29.15276 39.67774 -21.64 -2.73 0.39 0.51 -0.123 IZMI 27.08182 38.39481 -19.57 -17.17 0.53 0.68 -0.008 KIKA 27.67221 39.10599 -19.68 -11.08 0.40 0.53 -0.049 MUGL 28.36444 37.21636 -14.47 -20.01 0.59 0.76 -0.079 SALH 28.12355 38.48309 -22.22 -10.52 0.57 0.72 -0.028 USAK 29.40522 38.67921 -19.57 -8.37 0.40 0.56 -0.150
STATIONS OF TURDEP PROJECT AKHT 27.89513 38.99753 -20.02 -10.37 0.34 0.49 -0.059 BDMT 28.04087 38.12027 -18.73 -13.61 0.43 0.58 -0.061 BORT 28.55090 38.75191 -21.50 -9.38 0.39 0.53 -0.114 CALT 29.40375 37.99182 -19.07 -8.16 0.40 0.57 -0.193 ESMT 29.10617 38.42497 -18.53 -9.98 0.77 1.10 -0.240 IZMT 27.19424 38.37510 -18.30 -17.83 0.40 0.55 -0.001 KRCT 28.66741 37.82766 -21.03 -15.31 0.80 0.93 -0.064 KRPT 27.81555 37.58215 -18.11 -22.43 0.41 0.59 -0.058 TRBT 27.39112 38.31378 -19.15 -16.50 0.44 0.59 -0.024 TRGT 27.90726 38.41491 -19.84 -15.39 0.71 1.08 -0.150
IGS STATIONS TUBI 29.45068 40.78672 -2.67 -1.57 0.33 0.43 -0.190 ISTA 29.01934 41.10445 0.98 -2.17 0.29 0.38 -0.163 BUCU 26.12574 44.46394 0.75 -1.70 0.30 0.34 -0.006 GLSV 30.49673 50.36418 -0.35 -0.00 0.35 0.58 0.342 NICO 33.39644 35.14099 -2.67 3.21 0.42 0.69 -0.630 MATE 16.70446 40.64913 1.15 2.89 0.57 0.42 0.576 MIKL 31.97284 46.97278 0.93 0.08 0.42 0.47 0.227 PENC 19.28153 47.78960 0.73 -0.10 0.48 0.40 -0.474 WTZR 12.87891 49.14420 -0.26 -1.69 0.74 0.44 -0.512 ZECK 41.56506 43.78839 1.65 2.34 0.73 0.36 -0.269
67
Table 3.5 Horizontal GPS velocities of General Command of Mapping stations in a Eurasian fixed
frame and 1-σ uncertainties (plotted with 95% confidence ellipses in Figure 3.41) (Here, σν E and σνN
are 1-σ uncertainties of E (east) and N (north) respectively, ρνEνN is correlation coefficient between E
(east) and N (north) uncertainties).
Site Longitude (º)
Latitude (º)
νE (mm/yea
r)
νN (mm/year)
σνE (mm/year)
σνN (mm/yea
r)
ρνEνN
BAYO 27.30801 38.71103 -23.12 -15.53 0.65 0.74 -0.076 CEIL 26.38529 38.31084 -24.54 -27.60 4.65 5.07 -0.069
CKOY 26.23337 38.28772 -18.23 -24.92 1.06 1.18 -0.166 EMET 29.24559 39.33510 -23.30 -7.08 0.48 0.57 -0.153 LTFY 28.41285 39.99288 -19.16 -4.31 0.76 0.77 -0.074 YENF 26.79080 38.74109 -20.05 -16.85 4.53 4.18 -0.066 ZEYT 26.49654 38.20466 -19.55 -23.18 1.53 1.72 -0.116
IGS stations TUBI 29.45068 40.78672 0.33 -3.82 0.18 0.23 -0.261 ISTA 29.01934 41.10445 3.27 -3.60 0.16 0.21 -0.241
BUCU 26.12574 44.46394 -0.04 -1.11 0.15 0.17 -0.075 GLSV 30.49673 50.36418 -1.26 0.63 0.19 0.32 0.371 NICO 33.39644 35.14099 -4.70 3.56 0.26 0.42 -0.632 MATE 16.70446 40.64913 1.36 3.59 0.34 0.24 0.569 MIKL 31.97284 46.97278 -0.04 -0.80 1.61 1.98 -0.050 PENC 19.28153 47.78960 0.56 -0.06 0.29 0.24 -0.485 WTZR 12.87891 49.14420 -0.22 -0.82 0.43 0.23 -0.606 ZECK 41.56506 43.78839 0.69 2.90 0.45 0.21 -0.284
In Figure 3.41, it was seen that the velocity values were similar and
approximately 20-25 mm/yr for all stations. It was noticed that the directions of
velocities began to change from North to South. Although, the locations of TRGT
and SALH were close to each other, the velocity directions were different. Due to
this case, it may be said that these stations were located on the different mechanisms
from each other. Additionally, it was shown that the rotation of the velocity
directions to SW direction was started from the area between TRGT and SALH
stations.
68
Figure 3.41 GPS horizontal velocities and their 95% confidence ellipses in a Eurasia-fixed reference
frame for the period of 2009-2011 for TURDEP and CORS-TR stations which are shown by red
vectors and for the period of 2000-2001-2004 and 2005 for General Command of Mapping stations
which are shown by green vectors.
The obtained velocities from this study and the velocities of previous study which
were obtained by McClusky et al., (2000) and TUBITAK project No:108Y285 were
plotted together for examining the velocity changes of the study area during the years
(Figure 3.42 a). In the study of McClusky et al. (2000), GPS data were belong to the
years between 1988-1997 and in the TUBITAK project No:108Y285, GPS data were
belong to the years between 2009-2011.
Generally, it can be said that there was no big change from 1997 until 2011 on the
directions and magnitudes of the velocities (Figure 3.42 a). On the other hand,
69
according to differences on velocity directions of the stations, the study area was
separated to four regions (Figure 3.42 b).
Figure 3.42 a) GPS horizontal velocities of the study McClusky et al. (2000) for the period 1988-1997
which are shown by black vectors and GPS horizontal velocities of the TUBITAK project
No:108Y285 for the period 2009-2011 which are shown by navy vectors with 95% confidence ellipses
in a Eurasia fixed frame are added to the study area stations given in Figure 3.41.
70
Figure 3.42 b) The stations which were given at Figure 3.42.a were separated to 4 regions and shown
by purple rectangulars.
In the 1st region, the directions of velocities were approximately westward. It was
shown that the rotation of the velocity directions was started from the south border of
the 1st region. In the 2nd region, the directions of velocities were approximately
southwest. In the 3rd and 4th regions, the southern components of velocities began to
dominate. The directions of the velocities in the 3rd region which includes Izmir and
its surrounding were separated from the 2nd region with their dominant Southwestern
components. In the 4th region, the south components of velocities were more
dominant than 3rd region stations. Consequently, it can be said that the velocity
directions of the stations rotated from west to southwest direction from North to
South (Figure 3.42 b).
71
Additionally, in four points there were closer stations. For the points of AKHT
and AKGA the directions of velocities didn't change from 1997 to 2011. For DEIR
and DMIR, it was seen that the velocity direction (of DEIR) moved to SW
(clockwise direction) relative to previous velocity (DMIR). For MUGL and MULA,
the motions of the points were coherently. In these studies, there were two common
stations as CESM and BAYO. For CESM, it was seen that the points moved with the
same velocity between the years 1997 and 2011. For BAYO, the point moved at anti-
clockwise direction from 1997 to 2005 (Figure 3.42).
3.7.1 Other Relatively Solutions
Reilenger et al. (2006) developed an elastic block model in Africa-Arabia-Eurasia
continental collision zone for constraining present-day plate motions (relative Euler
vectors), regional deformation within the interplate zone, and slip rates for major
faults. The block boundaries were determined by mapped faults, seismicity, and
historic earthquakes. They separated Turkey to 3 blocks/plates as Anatolian (AN)
block, Aegean (AG) block and Southwest Anatolian (SWAN) block. They calculated
the Euler Vectors relative to Eurasia for determining the block model. Euler vectors
for Anatolian block and Aegean block (fixed reference frame) relative to Eurasia
were given at Table 3.6. In this study, Aegean and Anatolian block fixed velocity
vectors were calculated by using Euler vectors (Reilinger et al., 2006) which
represent general kinematics in relative coordinate system (Figure 3.43 and Figure
3.45).
Table 3.6 Euler Vectors Relative to Eurasia (Reilinger et al., 2006)
Block Name Latitude (°N) Longitude (°E) Rate (°/Myr)
Anatolian 30.8 32.1 1.231
Aegean 15.9 52.3 0.563
72
3.7.1.1 Anatolian Block Solutions
The Anatolian Block solutions were obtained relative to the Euler vectors for
stations of TURDEP and CORS-TR project (Figure 3.43 a). According to the
velocity directions, the stations were grouped as 3 regions and 2 lines (Figure 3.43 b).
In Figure 3.43 b, it was noticed that the velocity directions of BALK and HARC
were towards approximately northward (the opposite side relative to the other
stations). Due to this case, it can be said that BALK and HARC were located at the
northern side of the North Anatolia Region (NAR) boundary which was given at the
study of Özkaymak et al. (2013). Besides, this case was coherent with the Northern
boundary on Western Anatolia which was given by in tectonic models of McKenzie
(1978), Dewey & Şengör (1979), Sözbilir & Emre, 1996 and Çemen et al. (2006).
Additionally, the Northern detachment fault which was given at study of Ersoy et al.
(2014) (Figure 3.44) may be the reason of this separation between the BALK-HARC
and the other stations.
The NE-SW directional grabens; Gördes, Demirci and Selendi grabens, were
located between the 1st and 2nd regions. This separation was symbolized by Line B in
Figure 43.b. These grabens may be the reason of the differences on the velocity
directions between the stations of 1st and 2nd regions. Although the velocity
directions of these stations were different, the magnitudes of velocities were similar
for these stations.
3rd region stations were affected by W-E directional graben system. Although, the
velocity directions of 1st and 3rd region were similar, the velocity magnitudes of 3rd
region stations were larger than the other.
CESM and MUGL were located outside of the graben system and the velocity
directions were different from the other stations. Although the stations were located
far away from each other, surprisingly, the directions and magnitudes of velocities
were found as similar.
73
Although, SALH and TRGT were located closer to each other, the differences on
the velocity directions were obtained as quite large (Figure 3.43.b). Same result for
these two stations was pointed out at Eurasia fixed frame solution (Figure 3.41).
Figure 3.43 a) The velocity field with 95% confidence ellipses of the stations computed in Anatolian
block frame from 3-year (2009, 2010 and 2011) GPS data.
74
Figure 3.43 b) The stations are separated to 3 regions and shown by red shapes. Line A shows the
boundary of North Anatolian Region (NAR). Line B shows the separation of the group 1 and 2.
75
Figure 3.44 Geological map of Western Anatolia and its surrounding (Modified from Ersoy et al.,
2014). The pink circles represent the 3 regions which were described in the text.
3.7.1.2 Aegean Block Solutions
In Figure 3.45, it was seen that the velocities of southern stations were slower
than the northern stations. It was noticed that the velocity directions of CESM and
MUGL were different from the other stations. While BALK and HARC moved
differently from the other stations in Anatolian block solutions, in Aegean block
solutions they moved together with the other stations. Additionally, the velocity of
KRPT station was very slow relative to Anatolian block and Eurasia fixed frame
solutions.
76
Figure 3.45 The velocity field with 95% confidence ellipses of the stations computed in Aegean fixed
reference frame from 3-year (2009, 2010 and 2011) GPS data.
77
CHAPTER FOUR
ANALYZING MASS CHANGES OF WESTERN ANATOLIA BY USING
MICROGRAVITY AND GPS DATA
Microgravity is a geophysical method which defines density changes under the
surface. The method is affected directly by subsurface density distribution and
especially the existence of the cavities creating a mass loss according to surrounding
environment. This also provides a great convenience to describe the underground
structure (Butler, 1984; Ioane & Ion, 2005; Reci et al., 2011). In the study of
Ergintav et al. (2007), the change in microgravity values at the same measurement
points were examined together with vertical changing of GPS data for determining
vertical deformation in the Marmara region.
At the present day, gravity studies carry out on the subjects such as monitoring
geothermal reserves, groundwater levels, volcanic activities, determination of fault
systems and mechanic connections of these systems, monitoring horst-graben areas,
and their stress deformation (Jentzsch et al., 2001; Battaglia et al., 2003; Carbone et
al., 2003; Zeeuw-van Dalfsen et al., 2006). This type of relations shows the vertical
surface movements, besides, represents the density and mass changes in the
subsurface structures. Continuous visualization of the movements in the investigation
area is an important key point for understanding seismic risk of the region (Pamukçu
et al., 2014 in-press).
In the studies of Dewey & Şengör, (1979) and Şengör et al., (1985), Western
Anatolian Region is defined as continental extensional area which deformed under
the effect of extensional forces in N-S direction since Miocene (Figure 4.1a). Also,
Western Anatolian region moves toward the SW with a velocity of cs. 2.0 cm per
year due to the convergence of African, Eurasian and Anatolian plates bordered by
Northern Anatolian fault zone (NAFZ) (Figure 4.1a) By this idea, GPS and
microgravity network system measurements of "Multi-Disciplinary Earthquake
Researches in High Risk Regions of Turkey Representing Different Tectonic
Regimes" (TURDEP) Project, which were realized between the years 2007 and 2009
in Western Anatolia, were evaluated together. In Figure 4.1, the locations of sites are
78
given. The data of the project were provided from The Scientific and Technological
Research Council of Turkey (TUBITAK), Marmara Research Center, Earth and
Marine Science Institute.
In this study, tectonically compensation or uncompensation concept of Western
Anatolia was investigated. According previous studies about isostatic model of
Western Anatolia (Pamukcu &Yurdakul, 2008) was defined as elastic plate model. In
this model, the lithosphere is gently flexed into broad upwards and downwards in the
region of large loads. The warping induces bending stresses. These stresses will be
relieved by brittle faulting in the upper crust and by some form of ductile flow in its
lower part. In between the brittle and ductile deformation fields there is an elastic
core, which apparently is able to support the stresses induced by flexure on long
geological time-scales (Watts, 2001; Pamukcu & Yurdakul, 2008). All these
consequences are the isostatic model of the Western Anatolia region which does not
fit the local Airy model and are consistent with the finding that 6 km of the Western
Anatolian lithosphere may be more resistant to the stresses induced by long time
scaled geological flexure (Pamukcu & Yurdakul, 2008). Besides these, in the region
that corresponds to high topography and low amplitude Bouguer gravity anomaly,
there is no significant increase in the depth of crust-mantle interface (Pamukcu &
Yurdakul, 2008). This result pointed out that there are uncompensation parts in the
region. These regions are defined as a structure involved high seismic, lots of porous
and liquid (Maggi et al., 2000; Watts, 2001).
According to this knowledge, the vertical directional behavior was examined of
the study region on the scope of compensation or uncompensation mechanism by
using GPS and microgravity data. In the study, for 3 years (2007-2008-2009) data of
the continuous GPS stations (Figure 4.1.b) and microgravity, which were obtained
simultaneously in the points of GPS stations, were used. The GPS data were
processed with GAMIT/GLOBK software and the Up values of solutions were used
for comparing with the microgravity data. After performing base corrections on
microgravity data, the graphics were prepared for GPS and microgravity data. The
relations between the changes on the graphics were tested by statistical method. The
positive, negative or non-relation between two data sets were examined. At the last
79
step, the results were interpreted with the earthquake distributions occurred in the
study area.
Figure 4.1 a) General tectonic of the Turkey NAFZ: North Anatolian Fault Zone, WAEP: Western
Anatolian Extensional Zone EAFZ:Eastern Anatolian Fault Zone. b) The locations of GPS and
microgravity stations.
80
4.1 Applications
4.1.1 GPS Data Processing
GPS and microgravity measurements were obtained simultaneously at 6 sites of
the TURDEP project for 4 days. The GPS measurements at AKHT (Akhisar,
Manisa), BORT (Borlu, Manisa), ESMT (Eşme, Uşak), CALT (Çal, Denizli), BDMT
(Bademli, İzmir) and KRCT (Karacasu, Aydın) were measured 24 hours for each day
between the days 139th and 142nd (as Julian days) of 2007, 2008 and 2009. In order to
define the site coordinates and velocities 9 IGS stations of which has a good
processing and measurement history as well as which can be used to calculate the
velocity vectors were chosen to circulate the network area. For defining Eurasia fixed
reference frame; TUBI (Turkey), ZECK (Russia), NICO (Cyprus), MIKL (Ukraine),
GLSV (Ukraine), BUCU (Romania), PENC (Hungary), WTZR (Germany) and
MATE (Italy) were chosen as IGS (International GNSS Service) stations. For the
processing of GPS observations, in addition to study area stations, observations of 9
IGS stations were also included in order to make a link between the local and global
networks. The GAMIT/GLOBK software were used to process the data and also
performed in order to determine the consistency among them by examining GPS
repeatabilities (Figure 4.2). From the repeatabilities it can be seen that North, East
and Up components of the stations are below 5 mm. The GPS data were proceed by
using ITRF 2008 relative to Eurasia fixed frame. The daily solutions (time-series) of
the stations were given in (Figure 4.3, 4.4, 4.5, 4.6, 4.7 and Figure 4.8).
81
Figure 4.2 WRMS repeatabilities of North-East-Up values from combination of 2007, 2008 and 2009
GPS data.
82
Figure 4.3 The daily processing results (between the days 139th and 142nd ) of AKHT stations between
the years 2007 and 2009.
83
Figure 4.4 The daily processing results (between the days 139th and 142nd ) of BORT stations between
the years 2007 and 2009.
84
Figure 4.5 The daily processing results (between the days 139th and 142nd ) of ESMT stations between
the years 2007 and 2009.
85
Figure 4.6 The daily processing results (between the days 139th and 142nd ) of CALT stations between
the years 2007 and 2009.
86
Figure 4.7 The daily processing results (between the days 139th and 142nd ) of BDMT stations between
the years 2007 and 2009.
87
Figure 4.8 The daily processing results (between the days 139th and 142nd ) of KRCT stations between
the years 2007 and 2009.
88
In the next step GPS data were processed by using ITRF 2008 (International
Terrestrial Reference Frame) relative to Eurasia fixed frame (Figure 4.9 and Table
4.1).
Figure 4.9 GPS horizontal velocities and their 95% confidence ellipses in a Eurasia-fixed reference
frame for the period of 2007-2009.
89
Table 4.1 Horizontal GPS velocities of study area sites in a Eurasian fixed frame and 1-σ uncertainties
(plotted with 95% confidence ellipses in Figure 4.9)
Site Longitude
(º)
Latitude
(º)
νE
(mm/year)
νN
(mm/year)
σνE
(mm/year)
σνN
(mm/year) ρνEνN
AKHT 27.89513 38.99753 -21.80 -13.58 0.68 1.01 -0.139
BORT 28.55090 38.75190 -20.21 -9.51 0.77 1.08 -0.195
ESMT 29.10617 38.42497 -18.53 -9.98 0.77 1.10 -0.240
CALT 29.40375 37.99182 -18.06 -9.05 0.82 1.17 -0.264
BDMT 28.04087 38.12027 -18.72 -14.48 0.87 1.21 -0.130
KRCT 28.66741 37.82766 -19.28 -16.46 0.83 1.20 -0.200
σνE and σνN are 1-σ uncertainties of E (east) and N (north) respectively.
ρνEνN is correlation coefficient between E (east) and N (north) uncertainties.
4.1.2 Comparison of GPS and Microgravity Results
The gravity changes of the stations between the years of 2007 and 2009 were
given in Figure 4.10 a), 4.11 a), 4.12 a), 4.13 a), 4.14 a) and in Figure 4.15 a).
The Height (Up) values of the GPS daily solutions (at the 3rd graphics of Figure
4.3, 4.4, 4.5, 4.6, 4.7 and 4.8), which present vertical displacements were used for
calculating the displacement changes on the vertical directions from the years of
2007 to 2009. These displacement changes were given in Figure 4.10 b), 4.11 b),
4.12 b), 4.13 b), 4.14 b) and in Figure 4.15 b).
90
Figure 4.10 a) Gravity changes of AKHT stations between the years 2007-2009 b) Displacement
changes on vertical direction of AKHT stations between the years 2007-2009
Figure 4.11 a) Gravity changes of BDMT stations between the years 2007-2009 b) Displacement
changes on vertical direction of BDMT stations between the years 2007-2009
91
Figure 4.12 a) Gravity changes of KRCT stations between the years 2007-2009 b) Displacement
changes on vertical direction of KRCT stations between the years 2007-2009
Figure 4.13 a) Gravity changes of BORT stations between the years 2007-2009 b) Displacement
changes on vertical direction of BORT stations between the years 2007-2009
92
Figure 4.14 a) Gravity changes of CALT stations between the years 2007-2009 b) Displacement
changes on vertical direction of CALT stations between the years 2007-2009
Figure 4.15 a) Gravity changes of ESMT stations between the years 2007-2009 b) Displacement
changes on vertical direction of ESMT stations between the years 2007-2009
93
In this step, GPS and gravity measurement results according to time (their
increase/decrease relations) are valuable data for explaining deformation of station
region. In this study, after preliminary analyses, statistical relations were investigated
by correlation analyses. As it is known, correlation coefficients ( 11 ≤≤− r ) having
positive values show positive relation between two variables and negative values
show the opposite. Formula of the correlation coefficient was given in Equation 4.1.
Correlation coefficients calculated from GPS and gravity measurement results were
given in Table 4.2.
∑ ∑
∑
∑∑∑
−
−
−
−
==−−
−−
2222
YYXX
YYXX
yx
yxr
ii
ii
ii
ii (4.1)
Table 4.2 Correlation coefficients of GPS and gravity observation results.
Station Id r
AKHT -0.346885691
BDMT 0.246857117
KRCT -0.096857941
BORT 0.918876629
CALT 0.83879388
ESMT 0.525559851
For discussing the stations, it is needed earthquakes and topography map of the
study area. For this purpose, the earthquakes occurred between the latitude 36.40º
and 39.50º, longitude 26.20º and 30.00º; between the years 2005 and 2014, with the
amplitude range between 2.5 and 9.0, were taken from Boğaziçi University Koeri
National Earthquake Monitoring Center (Figure 4.16). Additionally, topographic
map of the study area was drawn by using the topographic data TOPEX (Figure
94
4.17.a). For discussing the earthquakes and topographic changes on the station point,
the cross-sections were taken which was shown in Figure 4.17.b.
Figure 4.16 The Earthquakes distributions which occurred between the years 2005-2014.
95
Figure 4.17 a) Topographic map of study area b) The blue lines show the cross-sections
The earthquakes distributions near to all stations and topographic changes along
to the cross sections (Figure 4.17 b) were shown in Figure 4.18, 4.19, 4.20, 4.21, 4.22
and Figure 4.23.
96
Figure 4.18 a) The topographic changes along to cross-section A-A' b) Earthquake distributions along
to S-N direction near to AKHT station. Small Red square shows the location of the station.
Figure 4.19 a) The topographic changes along to cross-section B-B' b) Earthquake distributions along
to S-N direction near to BDMT station. Small Red square shows the location of the station.
97
Figure 4.20 a) The topographic changes along to cross-section C-C' b) Earthquake distributions along
to S-N direction near to KRCT station. Small Red square shows the location of the station.
Figure 4.21 a) The topographic changes along to cross-section D-D' b) Earthquake distributions along
to S-N direction near to BORT station. Small Red square shows the location of the station.
98
Figure 4.22 a) The topographic changes along to cross-section E-E' b) Earthquake distributions along
to S-N direction near to CALT station. Small Red square shows the location of the station.
Figure 4.23 a) The topographic changes along to cross-section F-F' b) Earthquake distributions along
to S-N direction near to ESMT station. Small Red square shows the location of the station.
99
For understanding the vertical directional behavior of the region and the active
tectonic structures in the Western Anatolia extensional system, the vertical (Up)
solutions of GPS data and microgravity data were compared together. Results related
to vertical displacement belonging to time dependent microgravity and GPS data
between 2007 and 2009 years were presented in between Figure 4.10 and Figure
4.15.
If the correlation coefficient value is negative and near to -1, it can be said that the
region is in compensation balance and there is not any structural problem on crust. In
a balanced region while movement is in negative direction (-) according to isostasy,
gravity value should be positive. According to Table 4.2 which gave the correlation
coefficient between GPS and microgravity data, some opinions were expressed about
the measurement stations.
AKHT (Akhisar/Manisa) :
AKHT station which is located northern side of Gediz graben (Figure 4.17 a). It
has approximately 780 m height (Figure 4.18 a).
The correlation coefficient (r) of the station is negative but below −0.5
(r=−0.346885691) (Table 4.2). This result shows that in the station there is not an
expected relation (r = -1 or near to -1) between the GPS and microgravity data. It is
noticed that while the amplitude of the gravity, which are related with the deep
subsurface structures, are increasing year by year (Figure 4.10 a), the vertical
displacement is decreasing and then increasing (Figure 4.10 b)
In Figure 4.18b), it is seen that the earthquakes occurred up to 20 km depth. The
high seismicity may be the reason of lack of expected relation between GPS and
gravity data.
Additionally, it can be said that the seismic activity of the region may be the
source which causes irrelevant on equilibration mechanism of surface and subsurface
structures.
100
BDMT (Bademli, Ödemiş/İzmir):
BDMT station is located southern side of Küçük Menderes graben (Figure 4.17 a)
It has approximately 400 m. height and it is located on a flat area between two uplift
structures (Figure 4.19 a).
The correlation coefficient (r) of the station is positive but below +0.5 (r = 0.2)
(Table 4.2). If the value is below 0.5, it means that there is not an expected relation
(r=-1 or near to -1) between the GPS and microgravity data in this station.
In Figure 4.19b) it is noticed that the station point doesn't show seismic activity. It
can be said that existing of the Ödemiş geothermal source causes the non-seismicity.
Therefore, the lack of linear relation between the data sets may be explained by
existing of the geothermal sources.
The low density values of the geothermal sources decrease the amplitude of the
gravity. In Figure 4.11a), it is seen that the amplitude of gravity was decreasing year
by year. Therefore, the decreasing of gravity amplitude supports this information.
In Figure 4.11b), it is noticed that the vertical movement is increasing and then
decreasing. According to the uplift and collapse in vertical movement, it can be
suggested that the geothermal sources cause the irrelevant on equilibration
mechanism of surface and subsurface structures.
It can be said that there is a crustal problem on the station point because of the
uncompensation of surface and subsurface loadings.
KRCT (Karacasu/Aydın):
KRCT station is located southern side of Büyük Menderes graben (Figure 4.17 a)
and it is seen at cross-section in Figure 4.20.a it is located on the descending area.
Besides, it has approximately 700 m. height.
The correlation coefficient (r) of the station is negative but below −0.5 (r = −0.09)
(Table 4.2). This result shows that in the station there is not an expected relation (r =
-1 or near to -1) between the GPS and microgravity data.
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In Figure 4.20 b), it is noticed that while the northern side of the KRCT station
has high seismic activity, the southern side has low seismic activity relative to the
northern side. It can be said that this station is located on a boundary.
BORT (Borlu/Manisa):
BORT station is located northern side of Gediz graben (Figure 4.17 a) and it is
seen at cross-section in Figure 4.21a) it is located on the rising area. Besides, It has
approximately 600 m. height.
The correlation coefficient (r) of the station is positive (r = 0.9) (Table 4.2) and
there is a positive relation between GPS and gravity data. The station presents
increased and decreased gravity value in response to increased and decreased vertical
changes (Figure 4.13 a). It means that the surface loadings and subsurface loadings
move at the same direction. Therefore, it can be said that the station has not any
isostatic balance. This may be possibly considered as uncompensation in load
distribution arising from mass loss occurring subsurface due to the effects of
geothermal environment, subsurface water, or seismic activity (Pamukcu et al.,
2014).
BORT station is near to Köprübaşı-Saraycık geothermal system. (Mineral
Research & Exploration General Directorate [MTA], 2005). At this region, the hot
water goes up to the surface by itself. This system is related with a young basin,
which is arised by NNS-SSW directional oblique fault at Quaternary. The basin
occurred at uplifting area between two important grabens at Northern and Southern
sides and completed formation at the end of the Miosen. This basin is the youngest
geothermal system in Western Anatolia (MTA, 2005).
In Figure 4.21b), it is seen that there is not high seismic activity in BDMT station
point. The existing of geothermal activity is coherent with the non-seismicity in the
region.
102
CALT (Çal/Denizli):
CALT station is located at eastern side of the graben system with approximately
800 m height (Figure 4.17 a).
The correlation coefficient (r) of the station is positive (r = 0.8) (Table 4.2) and
there is a positive relation between GPS and gravity data. The station presents
decreased gravity value in response to decreased vertical changes (Figure 4.14 a-b).
It means that the surface loadings and subsurface loadings move at the same
direction. It can be said that in CALT station point there is not any isostatic balance.
Additionally, due to the decreasing the amplitude of gravity, it can be said that there
is a crustal problem at this station region.
The Karaahayıt geothermal region is approximately 30 km far away as the crow
flies from CALT station. In this geothermal region, lots of hot water sources go up to
surface and the bed rock is quartzite and marble (Şimşek & Eşder, 1981; MTA,
2005).
In Figure 4.22b) it is noticed that while the southern side of the CALT station has
high seismic activity, the northern side has low seismic activity relative to the other
side. It can be said that this station is located on a boundary. The fault system has
non-stabile structures which causes high deformation.
ESMT (Eşme/Uşak):
ESMT station is located at eastern side of the graben system with approximately
780 m height (Figure 4.17 a).
The correlation coefficient (r) of the station is positive (r = 0.5) (Table 4.2) and
there is a positive relation between GPS and gravity data.
In Figure 4.15a) it is noticed that the amplitude of gravity was decreasing year by
year. It can be said that there is a crustal problem on the station point because of the
uncompensation of surface and subsurface loadings (Pamukçu & Yurdakul, 2008;
Çifçi et al., 2011 and Pamukçu et al., 2014).
103
The ESMT station is near to the Örencik geothermal region. Hot waters go up to
surface through the N-S and E-W directional faults. The reverse volcanic activities
continued up to Quaternary in the region (Iça, 1978; MTA, 2005).
In Figure 4.23b), it is noticed that the seismic activity is low at the station point.
This case can be related with the existing of Örencik geothermal source.
104
CHAPTER FIVE
COULOMB STRESS CHANGES CALCULATIONS
Coulomb 3.3 software (Toda et. al, 2005; Lin & Stein, 2004) is used for
calculating static displacements (at GPS stations), strains, and stresses at any depth
caused by fault slip In this software, the calculations are performed in an elastic half
space with uniform isotropic elastic properties which explained by Okada (1992).
The Coulomb stress change which is on a specified fault depends on the fault
geometry and sense of slip, and the coefficient of friction but it is independent of
regional stress (King et al., 1994). In this study this method was used to resolve
stress changes on Northern and Southern Normal faults of Gediz Graben.
In the Coulomb criterion, when the Coulomb stress σ f exceeds a specific value,
failure consists on a plane is given as;
σ f = τβ - µ (σβ - p) (5.1)
where τβ is the shear stress on the failure plane, σβ is the normal stress, p is the pore
fluid pressure and µ is the coefficient of friction. The value of τβ must be positive in
this statement. The stress on fault plane get negative or positive value depends on
whether the slip of fault is right or left lateral. Therefore, the sign of τβ must be
chosen properly (King et al., 1994).
If the failure plane is directed at β to the σ1 axis (Figure 5.1), the stress
components can be described in the terms of principal stresses,
𝜎𝛽 = 12
(𝜎1 + 𝜎3) − 12
(𝜎1 − 𝜎3) cos 2𝛽 (5.2)
𝜏𝛽 = 12
(𝜎1 − 𝜎3) sin 2𝛽 (5.3) where σ1 is the biggest, σ3 is the smallest principal stress. In this way, Equation 5.1
becomes;
105
𝜎𝑓 = 12
(𝜎1 − 𝜎3)(𝑠𝑖𝑛2𝛽 − 𝜇𝑐𝑜𝑠2𝛽) − 12𝜇(𝜎1 + 𝜎3) + 𝜇𝑝 (5.4)
Figure 5.1 The axis system used for Coulomb stresses calculations of on optimum failure planes.
Compression and right-lateral shear stress on the failure plane are taken as positive. The sign of 𝜏𝛽 is
negative for calculations of right-lateral Coulomb failure on specified failure planes. (King et. al, 1994)
Pore fluid pressure affects the normal stress across the fault plan, as given in
equation (1). If the rock stress is changed faster than fluid pressure, p can be related
to stress in the rock by a coefficient which calls Skempton’s pore pressure parameter,
B. The value of B varies between 0 and 1. Therefore, Equation 5.1 can be simplified
by taking account assumptions for pore fluid pressure and Equation 5.1 becomes;
𝜎𝑓 = 𝜏𝛽 − 𝜇′𝜎𝛽 (5.5)
where the coefficient of friction is described by µ' = µ (1-B) (King et al.,1994).
If the x and y axes and fault displacements are at horizontal direction, and fault
planes are at vertical direction (along z direction), stress on a plane at an angle
ψ from the x-axis (as shown in Figure 5.1) is given as (King et al.,1994),
𝜎11 = 𝜎𝑥𝑥𝑐𝑜𝑠2𝜓 + 2𝜎𝑥𝑦𝑠𝑖𝑛𝜓𝑐𝑜𝑠𝜓 + 𝜎𝑦𝑦𝑠𝑖𝑛2𝜓
106
𝜎33 = 𝜎𝑥𝑥𝑠𝑖𝑛2𝜓 + 2𝜎𝑥𝑦𝑠𝑖𝑛𝜓𝑐𝑜𝑠𝜓 + 𝜎𝑦𝑦𝑐𝑜𝑠2𝜓
𝜏13 = 12
�𝜎𝑦𝑦 − 𝜎𝑥𝑥�𝑠𝑖𝑛2𝜓 + 𝜏𝑥𝑦𝑐𝑜𝑠2𝜓 (5.6)
5.1 Applications
Coulomb 3.3 graphic-rich stress change software (Toda et. al, 2005; Lin & Stein,
2004) was used for GPS velocity modeling and resolving stress changes on the faults
which have enough GPS stations at their northern and southern sides (Figure 3.7).
Therefore, according to locations of the GPS stations, Northern normal fault of Gediz
Graben and Southern normal fault of Büyük Menderes Graben were modeled.
The GPS data were processed with GAMIT/GLOBK (Herring et al., 2010a,
Herring et al., 2010b) software. In GPS processing, the solutions were done relative
to the stations which were located on opposite sides of the fault. It means that when
calculating the velocity of the stations which were located at one side, the opposite
side stations were assumed like as stabile (not moving). Therefore, the effect of the
fault on the GPS stations can be interpreted.
In the second step, by using the fault parameters (rake angle, dip angle, frictional
coefficient) (Figure 5.2) (Bozkurt & Sözbilir (2004) for Gediz Graben and Sümer et
al. (2013) for Büyük Menderes Graben), and elastic parameters (Poisson's ratio,
Young Modulus, Byeerlee's law friction), Coulomb 3.3 software modeled GPS
velocity vectors. By taking into account the GPS velocities which are obtained by
GAMIT/ GLOBK software, two types of GPS velocities (modeled and obtained)
were compared and tried to do best fitting between them.
In the third step; the coulomb stress changes were calculated by using the best
fitting fault parameters, which were determined from the observed and modeled GPS
vectors. Finally as the last step, the coulomb stress changes were compared with the
occurred earthquakes between the years 1970 and 2014.
107
Figure 5.2 The parameters of fault geometry (Aki & Richards, 1980).
5.1.1 Northern Normal Fault of Gediz Graben
For GAMIT/GLOBK processing, the stations; AKHT (Akhisar, Manisa), BORT
(Borlu, Manisa), ESMT (Eşme, Usak) and CALT (Çal, Denizli) which were located
at north side and TRGT (Turgutlu, Manisa) and SALH (Salihli, Manisa) were located
at south side of Northern Normal fault of Gediz Graben were chosen. In Figure 3.7, it
was noticed that BAYO was located near to the fault but its observation days were
not same with the other stations. Therefore, BAYO couldn’t be taken into processing
with the other stations.
The GPS velocities of northern side stations (AKHT, BORT, ESMT, CALT) were
calculated relative to Southern stations (by assuming the movements of southern
stations are zero) and GPS velocities of southern side stations (TRGT and SALH)
were calculated relative to Northern stations (by assuming the movements of
Northern stations are zero) for the days between 180th and 195th, the years of 2009,
2010 and 2011 (Figure 5.3).
As the second step, in Coulomb 3.3 software, Poisson ratio; 0.25, Young
Modulus; 8·105 bars, and friction coefficient; 0.4 were chosen as elastic parameters.
For the fault parameters, dip angle; 60°, rake; -70° and strike; 117° were given the
best fitting between the observed by GAMIT/GLOBK and modeled by Coulomb 3.3
(Figure 5.4) GPS velocities. Additionally, the bottom depth of the fault was given 4
km by taking the study result of Çiftçi & Bozkurt (2010).
108
In Figure 5.3, it was noticed that the movements of TRGT and SALH were
different from each other and besides, the movements of ESMT and CALT were
different from BORT as in the Chapter three in Eurasia, Anatolia and Aegean block
fixed results (Figure 3.43 and Figure 3.45).
Figure 5.3 GPS velocities of North stations (AKHT, BORT, ESMT and CALT) and South stations
(TRGT and SALH ) relative to each other.
109
Figure 5.4 Blue vectors represent the obtained GPS velocities by Gamit/Globk and red vectors
represent modeled GPS velocities by Coluomb 3.3
In Figure 5.4, it was seen that, the modeled and observed GPS velocities were
fitted at AKHT, BORT and TRGT. But there was not compliance between the
velocities for SALH. Additionally, Coulomb software can not model velocities for
ESMT and CALT stations due to their far away locations from the fault.
According to observed and modeled GPS velocities (Figure 5.3 and Figure 5.4), it
can be said that BORT and TRGT stations were coherent with the N-S directional
extension system. However, SALH was not moving properly with this system. It was
thought that this case was occurred since its location was near to Northern normal
fault as well as Southern normal fault of Gediz Graben. Therefore, it can be said that
SALH was affected by both faults (Figure 5.3 and Figure 5.4).
In the next step, by using the best fitting parameters (Figure 5.5), which obtained
from the observed and modeled GPS vectors, the coulomb stress changes were
110
calculated and plotted for the depths of 4 km and 6 km and additionally for the depth
range between 0-4 km and 0-6 km (Figure 5.6, 5.7, 5.8 and Figure 5.9).
Figure 5.5 The view of ‘stress control panel’ of Coulomb 3.3 software for calculating Coulomb Stress
Changes for the northern normal fault of Gediz Graben at 6 km depth.
111
(a)
(b)
Figure 5.6 a) Coulomb stress changes between the depths of 0-4 km. b) Earthquake focus distributions
on the study area. USGS earthquake archive was used between the years 1970-2014.
112
(a)
(b)
Figure 5.7 a). Coulomb stress changes at depth 4 km. b) Earthquake focus distributions on the study
area. USGS earthquake archive was used between the years 1970-2014.
113
(a)
(b)
Figure 5.8 a) Coulomb stress changes between the depths of 0-6 km. b) Earthquake focus distributions
on the study area. USGS earthquake archive was used between the years 1970-2014.
114
(a)
(b)
Figure 5.9 a) Coulomb stress changes at depth 6 km. b) Earthquake focus distributions on the study
area. USGS earthquake archive was used between the years 1970-2014.
115
It was noticed that for the all different depth figures (Figure 5.6 a), 5.7 a), 5.8 a)
and Figure 5.9 a)) the coulomb stress change values were similar on the stations
points. Additionally, the SALH was located on the main stress region caused by the
fault because its location was very near to the fault. Besides, this case can be the
reason of the inability of the previous step for SALH. As the result of the seismic
activity, the non-stabile duration of subsurface structures which were in the stress
region can contain air, water, etc. Therefore, it can be seen some problems on
modeling of the non-stabile region like as SALH.
For investigating the stress source depth, the coulomb stress changes were
calculated for the depths of 4 km and 6 km (Yurdakul, 2007; Pamukçu & Yurdakul,
2008) and additionally for the depth range between 0-4 km and 0-6 km (Figure 5.6 a,
5.7 a, 5.8 a and Figure 5.9 a). It is determined that the depth of fault (4 km), which
was given at previous Coulomb GPS velocity modeling step, is the initial depth of
the stress (Figure 5.6 a and Figure 5.7 a) and it is seen that the stress still continue at
6 km depth (Figure 5.8 a and Figure 5.9 a). Consequently, it can be said that the
stress area has regional effects for the depth range between 0-4 km. At deeper depth
than 4 km, the stress area (deformed area) had total regional effects.
As the last step, the coulomb stress change values were compared with the
earthquake focus distributions which were obtained from USGS (United States
Geological Survey) between the years 1970-2014. For this study the earthquakes
which occurred up to 7km depth were drawn since the bottom depth of the fault was
chosen as 4 km (Figure 5.6 b, 5.7 b, 5.8 b and Figure 5.9 b). It was noticed that the
earthquakes which occurred near the modeled fault are seen on high stress region
(red colored areas) and at the NW side of the modeled fault (Figure 5.6 b, 5.7 b, 5.8 b
and Figure 5.9 b). The earthquakes were coherent with the high stress region at the
west and east boundaries of the fault. But there was an incompatible case at NW of
the fault. In the study, this NW side of the fault could not be modeled. AKHT station
was located north side of the fault, but also it was needed southern stations for
relatively calculations. Unfortunately, the GPS observation days of BAYO, YUNT
stations (Figure 3.7) were less as well as not the same days with the other stations to
process together. Therefore, the fault was modeled as the limits of the locations of
116
GPS stations. For better solutions, it is needed to build more GPS stations for
investigating the effects of the faults.
Finally, Coulomb 3.3 software calculated the earthquake magnitude by using the
input fault parameters as M=4.0. The earthquakes occurred with magnitude 4
intensively, between the years 1970-2014 at the study area. These two values are
coherent with each other.
5.1.2 Southern Normal Fault of Büyük Menderes Graben
The stations; BDMT (Bademli, Manisa), AYD1 (Aydın, Merkez), CALT (Çal,
Manisa) which were located at north side and KRPT (Karpuzlu, Aydın), KRCT
(Karacasu, Aydın) and DENI (Denizli, Merkez) which were located at south side of
Southern Normal fault of Büyük Menderes Graben were chosen and were processed
by using GAMIT/GLOBK. The GPS velocities of northern side stations (BDMT,
AYD1, CALT) were calculated respect to Southern stations (by assuming the
movements of southern stations are zero) and GPS velocities of southern side
stations (KRPT, KRCT, DENI) were calculated respect to Northern stations (by
assuming the movements of Northern stations are zero) for the days between 180th
and 195th, the years of 2009, 2010 and 2011 (Figure 5.10).
In Coulomb 3.3, for elastic parameters; Poisson ratio; 0.25, Young Modulus;
8⋅105 bars, friction coefficient; 0.4 were chosen as elastic parameters. In this part, the
fault was designed as two faults. For the 1st fault parameters; rake; -95º and dip
angle; 70º and for 2nd fault, rake; -75º and dip angle; 77º were given the best fitting
between the observed and modeled (Figure 5.11) GPS velocities. Additionally, the
bottom depths of the fault were chosen as 5 km for the 1st fault and 3 km for the 2nd
fault (Çiftçi et al., 2011).
In the Coulomb 3.3 software GPS velocity modeling step, DENI and AYD1
stations were moved from the calculations. Since according to GAMIT/GLOBK
processing results, DENI has no velocity and the velocity of AYD1 is in the error
ellipses (Figure 5.10).
117
Figure 5.10 GPS velocities of North stations (AYD1, BDMT and CALT) and South stations (KRPT,
KRCT and DENI ) relative to each other.
Figure 5.11 Blue vectors represent the obtained GPS velocities by GAMIT/GLOBK and red vectors
represent modeled GPS velocities by Coluomb 3.3. No: 1 represents 1st fault and No: 2 represents 2nd
fault.
118
In Figure 5.10, it can be said that KRPT and CALT were moving coherently with
the main N-S extensional features of the Western Anatolia. Also, as well as the
magnitude of velocities of BDMT and KRCT were small, they were moving
coherently with the N-S extensions. AYD1 was moving differently from the other
stations but at the same time the velocity magnitude was in the error ellipse. The
location of the station where was very near to the fault may be the reason of this
problem. From the relatively solutions DENI was found as stabile respect to opposite
side stations (Figure 5.10).
In Figure 5.11, it was seen that, the modeled and observed GPS velocities were
fitted for KRPT and KRCT. The coherence between the modeled and observed
velocities for CALT was not well. Additionally, the modeled and observed velocities
of BDMT had same directions and they were fitted but the magnitude of the modeled
velocity was higher than the observed one (Figure 5.11).
As the next step, for calculating the coulomb stress changes, the software got the
mean values of dip and rake angles of two fault automatically (Figure 5.12) By these
parameters the coulomb stress changes were calculated and plotted for the depths of
3 km and 5 km and additionally for the depth range between 0-3 km and 0-5 km
(Figure 5.13, 5.14, 5.15 and Figure 5.16).
Figure 5.12 The view of ‘stress control panel’ of Coulomb 3.3 for calculating Coulomb stress changes
for the Southern normal fault of Büyük Menderes Graben at 3 km depth.
119
(a)
(b)
Figure 5.13 a) Coulomb stress changes between the depths of 0-3 km. b) Earthquake focus
distributions on the study area. USGS earthquake archive was used between the years 1970-2014.
120
(a)
(b)
Figure 5.14 a) Coulomb stress changes at 3 km depth. b) Earthquake focus distributions on the study
area. USGS earthquake archive was used between the years 1970-2014.
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(a)
(b)
Figure 5.15 a) Coulomb stress changes between the depths of 0-5 km. b) Earthquake focus
distributions on the study area. USGS earthquake archive was used between the years 1970-2014.
122
(a)
(b)
Figure 5.16 a). Coulomb stress changes at 5 km depth. b) Earthquake focus distributions on the study
area. USGS earthquake archive was used between the years 1970-2014.
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For investigating the stress source depth, the coulomb stress changes were
calculated for the depths of 3 km and 5 km and additionally for the depth range
between 0-3 km and 0-5 km (Figure 5.13 a, 5.14 a, 5.15 a and Figure 5.16 a).
Figure 5.13.a showed the coulomb stress changes at the depth range between 0-3
km and it was seen that KRCT, KRPT and CALT stations were in the high stress
region. However, in Figure 5.14.a which showed the coulomb stress changes at 3 km
depth, KRCT and KRPT were in low stress region. Therefore, it can be said that
surface and shallow structures up to 3 km effect KRCT and KRPT stations. Similar
opinions can be said for Figure 5.15.a which showed the coulomb stress changes at
depth range between 0-5 km and Figure 5.16.a which was drawn for 5 km for KRCT
and KRPT stations. BDMT station was located at low stress region at all depths and
Coulomb GPS vector modeling showed good fitting for this station. Contrarily, the
GPS vector modeling was not good and additionally, CALT was located at high
stress region at all depths. Consequently, it can be said that Büyük Menderes graben
was affected by stress area up to 3 km. At the depth deeper than 3 km, the stress area
(deformed area) had total regional effects.
As the last step, the coulomb stress change values compared with the earthquake
focus distributions which were obtained from USGS (United States Geological
Survey) between the years 1970-2014. For this study the earthquakes which occurred
up to 7 km depth were drawn since the bottom depth of the fault was chosen as 5 km
for the 1st fault and 3 km for the 2nd fault. The occurred earthquakes were coherent
with the coulomb stress change regions (Figure 5.13 b, 5.14 b, 5.15 b and Figure 5.16
b).
The normal faults of Küçük Menderes Graben and northern normal fault of Büyük
Menderes Graben can not be modeled due to the less station around these faults.
Additionally, the southern normal fault of Gediz Graben couldn't be modeled since
there is not enough GPS station surrounds the fault. As seen in Figure 3.7, there are
TRGT, SALH stations but they are located on the fault plane. If it is noticed that
there is only CALI station at the southern side but unfortunately the GPS data are not
enough for processing. Therefore because of the lack of GPS stations, the northern
normal fault of Gediz Graben cannot be modeled.
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5.1.3 The Relative Calculations on Study Area
For investigating the relative movements of the stations for different directions
some processing were done (Figure 5.17, 5.18, 5.19 and Figure 5.20).
Firstly, KIKA, AKHT and TRGT were chosen left side stations and DEIR,
BORT, USAK and ESMT were chosen as right side stations. Their movements were
processed relatively each other like described at previous part.
In Figure 5.17, it was noticed that the velocity directions of DEIR and BORT
were different from ESMT and USAK. Because of this inconsistency DEIR and
BORT were moved from the processing stations and the stations were processed
again (Figure 5.18). It was seen that after moving DEIR and BORT, the same group
stations ESMT and USAK did not effected but in other group stations KIKA, AKHT
and TRGT were affected. In the next step, DEIR and BORT were added to left
station group. In Figure 5.19, it was noticed that the velocity directions of DEIR and
BORT were different from the same group stations. Consequently, it can be said that
DEIR and BORT were located in a different structures from the surrounding stations.
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Figure 5.17 GPS velocities of left side stations (KIKA, AKHT and TRGT shown by black vectors)
and right side stations (DEIR, BORT, USAK and ESMT shown by red vectors) relative to each other.
Figure 5.18 GPS velocities of left side stations (KIKA, AKHT and TRGT shown by black vectors)
and right side stations (USAK and ESMT shown by red vectors) relative to each other.
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Figure 5.19 GPS velocities of left side stations (KIKA, AKHT, TRGT, DEIR and BORT shown by
black vectors) and right side stations (USAK and ESMT shown by red vectors) relative to each other.
In the next step, same application was done for the stations near to Büyük
Menderes Graben. Because at the previous processing of the stations near to Büyük
Menderes Graben, the velocity of AYD1 was calculated differently from the other
stations and DENI was found as approximately stabile (Figure 5.20). It was noticed
that BDMT, AYD1 and KRPT were moving to South, on the other hand, KRCT,
DENI and CALT were moving to North.
Consequently, for the relative applications of the stations near to Gediz Graben
and Büyük Menderes Grabens, it can be pointed out that there may be a zone at N-S
direction between the left and right stations. For relative solution results Gediz
Graben were consistent with the North part of IBTZ (Izmir- Balıkesir Tranfer Zone)
which was studied by Ersoy et al. (2014).
127
Figure 5.20 GPS velocities of left side stations (BDMT, AYD1 and KRPT shown by black vectors)
and right side stations (CALT, KRCT and DENI shown by red vectors) relative to each other.
128
CHAPTER SIX
NUMERICAL MODELING
Numerical modeling with finite element analysis is a computational tool that can
be used for calculating forces, deformations, stresses and strains throughout a bonded
structure. These predictions can be made at any point in the structure including
within the adhesive layer. Furthermore, the element mesh can accurately describe the
geometry of the bond line so the influence of geometrical features, such as the shape
of model and boundaries. Simulate the deformation of a continuous medium involves
performing set of equations that are not usually resolving directly. The spatial
discretization of the medium finite element associated with the time discretization is
used to give a digital nature to equations.
In this study, western Anatolia was modeled to investigating the deformation
during the geological scales. In this scope, the finite element modeling software,
namely, ADELI (Chery & Hassani, 2002) which was developed by using theoretical
equations given in Zienkiewicz (1977), Owen & Hinton (1980), Dhatt & Thouzot
(1981), Salençon (1995) was used for modeling the deformation. Additionally, the
details of the equations and the algorithm used in ADELI were given in Hassani
(1994) and Huc (1997).
6.1 Physical Problem (continuum) and Equilibrium Equations
Modeling of deformation on the lithosphere as a continuous medium is mainly
based on the equilibrium equations of the environment, the laws of behavior of this
medium, the boundary conditions of the environment as well as some initial
conditions.
The medium is considered as continuous which allows using the concepts of the
mechanical continuum to calculate the equilibrium of the system. Discontinuities
corresponding the faults modeled this behavior by law Coulomb friction-type are
treated as a boundary condition of a particular type. The equilibrium equations of the
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medium are defined on the current configuration Ct. If the medium continuously
occupied at time t Ct configuration, and if every point M belonging to Ct (is subject
volume) to the external forces 𝑓(M) and surface 𝐹(M), the resultant force is written
as (Salençon, 1995):
∫ 𝑓(𝑀) 𝑑Ω + ∫ 𝐹(𝑀)∂𝐶𝑡𝐶𝑡𝑑Γ = ∫ ρ(𝑀)𝐶𝑡
γ(𝑀)𝑑Ω (6.1)
and the resultant moment is:
∫ 𝑂𝑀 ∧ 𝑓(𝑀)𝑑Ω + ∫ 𝑂𝑀 ∂𝐶𝑡𝐶𝑡 ∧ 𝐹(𝑀)𝑑Γ = ∫ 𝑂𝑀 ∧ρ(𝑀)𝐶𝑡
γ(𝑀)𝑑Ω (6.2)
with ρ (m) density at point M and γ (m) acceleration at the same point.
For all volumes D included in Ct, if we assume that the efforts (stress, strain) of
the rest surface of the medium and are dependent on the normal n to the ∂D surface
Equation 6.1 becomes:
∀D ⊂ Ct ∫ 𝑓(𝑀) 𝑑Ω + ∫ T∂𝐷𝐷 �𝑀, n�𝑑Γ = ∫ ρ(𝑀)𝐷 γ(𝑀)𝑑Ω
(6.3)
For fixed M, T(𝑀,𝑛�) is a linear transformation function. T �𝑀, n � is contracted
product between the stress tensor Cauchy 𝜎� (M) and the normal 𝑛�:
T �𝑀, n � = 𝜎� (M) ⋅ n (6.4)
In Equation 6.2 if the stress tensor Cauchy 𝜎� (M) is symmetrical, Equation 6.4
becomes:
∀D ⊂ Ct ∫ �ργ − 𝑓� 𝑑Ω − ∫ σ �∂𝐷𝐷 n𝑑Γ = 0 (6.5)
130
Using the divergence, Equation 6.5 becomes:
∀D ⊂ Ct ∫ �ργ − 𝑓 − 𝑑𝑖𝑣(𝜎�)�𝐷 𝑑Ω = 0 (6.6)
As this relationship with the regardless of the volume D, the term goes to zero
under the integral (provided it is continuous) (Curnier, 1993). Therefore, we have:
in Ct ργ = 𝑓 + 𝑑𝑖𝑣(𝜎�) (6.7)
Here, ργ, 𝑓 and 𝑑𝑖𝑣(𝜎�) represent the acceleration forces, the external forces (volume
and surface) and the internal forces (stresses) respectively.
The stresses 𝑓 in the Equation 6.7:
-forces of volume: the density of force per unit volume is given by the field vectors:
𝑓𝑣 on Ct
The boundary conditions of the problem are:
-if kinematic: 𝑣 = 𝑣𝑑 on 𝜕𝐶𝑡𝑉 (limited velocity )
-if static : 𝜎� n = 𝑓𝑠 on 𝜕𝐶𝑡𝑃 (limited pressure)
-if the more specific terms as the contact between two bodies:
𝑓𝑐 on 𝜕𝐶𝑡𝐶 (mixed constraints limited on contact)
The overall outline of the medium is:
𝜕𝐶𝑡 = 𝜕𝐶𝑡𝑉 ∪ 𝜕𝐶𝑡𝑃 ∪ 𝜕𝐶𝑡𝐶 (6.8)
6.2 Constitutive laws
The constitutive equations are used to connect the stresses and strains of a given
medium. For describing the lithospheric rheology, while elastoplastic material is
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used at low pressure and low temperature, viscoelastic material is used at high
pressure and high temperature. One of the differences between two types of material
is the time-related behavior. While viscoelasticity is time-dependent, elastoplasticity
behavior is not dependent on time. In this sense the definitions of them are different
adopted in geology, where plasticity can also correspond to a viscous behavior.
6.2.1 Elastoplasticity
The behavior laws identify a perfectly elastic solid plastic. The simple analog
model corresponds to a linear spring and a pad in series given as in Figure 6.1.a. The
solid behaves elastic before reaching the threshold (limit) (σs). If reached, the solid
deforms plastically (Figure 6.1.b). The behavior is simpler than the rocks because the
constraint evolves beyond the threshold, which is not quite true for rock mechanics,
for which one can be problems positive (hardening) or negative (softening).
Figure 6.1 a) The model of elastoplastic material. b) The deformation of elastoplastic material due to
stress (modified from Vernant, 2003).
There are several laws to describe the elastic-plastic behavior of rocks. In this
study, two types of material, the Von Mises and Drucker-Prager materials were used.
In Von Mises material the threshold is constant and it is pressure-independent. On
the other hand, in the Drucker-Prager material, the threshold of plasticity changes are
related with mean stress, thereby increasing the resistance of rock is related with the
increasing of pressure (Jaeger & Cook, 1976; Byerlee, 1978).
The law used in our study is to Drucker-Prager material. The criterion load of the
form is (Leroy & Ortiz, 1989):
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𝑓(𝜎) = 𝐽2(𝜎) − 𝛼(𝑘) ∙ �𝜎� + 𝑐𝑡𝑎𝑛𝜑
� < (6.9)
here, 𝐽2 is finite strain and given as;
𝐽2(𝜎) = �32‖𝑑𝑒𝑣𝜎‖
𝛼 = 6𝑠𝑖𝑛𝜑
3 − 𝑠𝑖𝑛𝜑
𝜎� = −13𝑡𝑟(𝜎) (6.10)
where dev is the deviatoric part of the tensor, σ is the average stress, φ is angle of
internal friction and c is cohesion (Vernant, 2003).
6.2.2 Viscoelasticity
Viscoelasticity is the property of materials that exhibit both viscous and elastic
characteristics when undergoing deformation. The viscoelastic behavior occurs at
higher pressure and temperature, its movements associated with dislocation or
diffusion. Maxwell model which described the viscoelastic
behavior, behaves steady as a perfect fluid when the applied strain (deformation)
rate is constant. On the other hand, short-term model responds instant access to a
sudden load. The Maxwell model can be represented by a damper purely viscous (η)
and a purely elastic spring with Young's modulus (E) connected in series (Vernant,
2003) (Figure 6.2).
Figure 6.2 a) The model of viscoelastic material. b) The behavior of the viscoelastic solid (Modified
from Vernant, 2003).
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6.3 General Algorithm of the Finite Element Modeling Software (ADELI)
For 3D modeling of large deformations with code ADELI, computing
environment is discretized by tetrahedral finite elements with four nodes. The
discretization of the dynamic equation transforms the problem "continuum" in a
system of finite vector equations (three equations by mesh node).
The terms are obtained by assembling the contribution of each element, with the
M mass matrix, Fext the vector of external forces, Fint the vector of internal forces,
Fcont the contact force vector and the vector accelerations �̈� are given as (Vernant,
2003):
𝑀�̈� = 𝐹𝑒𝑥𝑡 + 𝐹𝑖𝑛𝑡 + 𝐹𝑐𝑜𝑛𝑡 (6.11)
According to Hassani (1994), the algorithm is as followings:
1. Calculation of the external forces: (𝐹𝑒𝑥𝑡)𝑛
2. Calculation of free residual: (𝑟𝑓)𝑛 = (𝐹𝑒𝑥𝑡)𝑛 + (𝐹𝑖𝑛𝑡)𝑛
3. Calculation of the acceleration:
�̈� = 𝑀−1 �(𝑟𝑓)𝑛 − 𝛼 ∙ 𝑠𝑔𝑛 ��̇�𝑛−12� �(𝑟𝑓)𝑛 + (𝐹𝑐𝑜𝑛𝑡)𝑛��
4. Calculation of velocity and displacement:
For velocity : ��̇�𝑓�𝑛+12 = ��̇��
𝑛−12 + ∆𝑡��̈��𝑛
For displacement: �𝑢𝑓�𝑛+1
= �𝑢�𝑛
+ ∆𝑡��̇��𝑛−12 + 1
2∆𝑡2��̈��
𝑛
5. Calculation of contact forces: (𝐹𝑐𝑜𝑛𝑡)𝑛+1
6. Corrections of velocity and displacement:
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For velocity : ��̇��𝑛+12 = ��̇�𝑓�
𝑛+12 + ∆𝑡𝑀−1 (𝐹𝑐𝑜𝑛𝑡)𝑛+1
For displacement: �𝑢�𝑛+1
= �𝑢𝑓�𝑛+1
+ 12∆𝑡2𝑀−1 (𝐹𝑐𝑜𝑛𝑡)𝑛+1
7. Updating coordinates: 𝑥𝑛+1 = 𝑋 + 𝑢𝑛+1
(X is the vector of initial coordinates)
8. Calculation of stress and the internal forces:
For stress : 𝜎𝑛+1
For internal forces: (𝐹𝑖𝑛𝑡)𝑛+1
9. Calculations of strain rate; 𝜀̇, for mantle and sub-lithospheric mantle:
𝜀̇ = 𝐴 · 𝜎𝑛 exp �− 𝑄𝑅∙𝑇�
Here, T; temperature, 𝜎 ; differential stress, A; viscosity parameter, n; stress
exponent, Q; activation energy, R; ideal gas constant.
6.4 Applications
In this study, Western Anatolia was modeled to investigating the deformation
during the years. In this scope, the finite element modeling software, namely, ADELI
(Chery & Hassani, 2002) which was developed by using theoretical equations given
in Zienkiewicz (1977), Owen & Hinton (1980), Dhatt & Thouzot (1981), Salençon
(1995) was used. Additionally, the details of the equations and the algorithm used in
ADELI were given in Hassani (1994) and Huc (1997).
Before starting the modeling with finite element code, ADELI, it was needed to
create the model with meshes. Therefore, for generating the meshes, a three-
dimensional finite element mesh generator tool, namely, ‘Gmsh’ (Geuzaine &
Remacle, 2009) was used. After processing, for viewing the outputs, a parallel
visualization application tool, namely, ‘Paraview’ (Moreland K., 2013) was used.
135
For giving idea about ADELI, a simple model was created. In this simple model,
the length; 20 km, weight; 10 km and the depth; 10 km were given. Firstly, the
geometry of model was drawn (Figure 6.3), then it was meshed in 3D (Figure 6.4).
Therefore, the model was ready for processing and in Figure 6.5, the initial model
was shown.
Figure 6.3 The simple model created with ‘gmsh’.
Figure 6.4 The view of 3D meshing with ‘gmsh’.
136
The density; 2.9 gr/cm3, Young modulus; 1.e11 and Poisson ratio; 0.25, the
viscosity parameter; 3e-22, stress exponent; 15 were given as model parameters.
However, temperature and pressure were ignored. In the model, center of the
material a curve was given. In the numerical modeling, for extend the model, the
extensional forces were given to two opposite surfaces of the initial model with the
2.5 mm/yr velocities (Figure 6.5). The modeling time was chosen as 1.1 Myr. For the
example, the deformed models which were created after 0.7 Myr and 1.1 Myr were
given in Figure 6.6 and Figure 6.7. By the years, the initial model was deformed,
extended and the finite strain changes were shown in these figures.
Figure 6.5 The view of initial model. Green arrows represent the extensional forces were given the
borders.
137
Figure 6.6 The view of finite strain (deviatoric epsilon) of model after 0.7 Myr.
Figure 6.7 The view of finite strain (deviatoric epsilon) after 1.1 Myr.
In this study, Western Anatolia was modeled from south to north for modeling the
extension. The south border of Menderes Extensional Metamorphic Complex
(MEMC) at south side and the North Anatolian Fault zone at north side were chosen
as the boundary conditions of the model (Figure 6.8). The length of the model was
chosen as 250 km, the weight was chosen as 20 km and the depth was chosen as 30
km (Figure 6.9).
138
In the modeling, the continental crust was modeled up to 30 km. The modeled
was separated to 3 layers at z-direction. First layer depth was chosen as 4 km since
the depth of Gediz graben is approximately 4 km (Çiftçi & Bozkurt, 2010). Second
layer depth was 7 km since the effective elastic thickness was approximately 7 km on
Western Anatolia (Yurdakul, 2007; Pamukçu & Yurdakul, 2008). The depth of third
layer was as 30 km for modeling the crust up to Moho depth (Pamukçu & Yurdakul,
2008, Zhu et al., 2006). At the first layer, 3 weakness zones were given in the initial
model (Figure 6.9).
For continental crust, rheologic parameter (Activation energy, viscosity parameter
and stress exponent) of Gleason & Tullis (1995) based on wet quartzite were used
(Table 6.1). As elastic parameters; Young modulus E = 1011 Pa and Poisson ratio ν=
0.25 (Turcotte & Schubert, 2002) were given. As density 2.4 g/cm3 for first layer, 2.9
g/cm3 for second layer and 3.1 g/cm3 for third layer were given. The densities of the
weakness zones at the first layer shown as No:1, 2 and 3 in Figure 6.4, were chosen
as 2.4 g/cm3. For giving extension to the model, the forces were affected to the x
direction. The velocities were given to the south and north borders of the model and
additionally, to the south border of the No:1 weakness zone and north border of the
No:3 weakness zone. In Chapter 3 at the Anatolian block solutions, the velocities
were found approximately 3 mm/yr (Figure 3.43). Therefore, this magnitude of
velocity used in the modeling. The all parameters used in the modeling were given at
Table 6.1. The finite element modeling software, ADELI, was used the equations
explained in the previous sections during the modeling.
Table 6.1 Physical parameters used in the numerical modeling.
Parameters Values Young Modulus (Pa) 1011
Poisson ratio 0.25 Viscosity Parameter (Pa-n s-1 )(A) 1.10-28
Activation Energy (kJ/mol) 223 Stress Exponent (n) 4 Frictional Coefficient 0.3 Pressure (Pa) 0.e25
139
Figure 6.8 The view of the profile length of the numerical model. In this figure Google Earth tool was
used.
Figure 6.9 The initial view of the model. No:1, No:2 and No:3 represent the weakness zones.
The topography (Figure 6.10) and crust-mantle interface values (Figure 6.11)
which were represented the Moho depth of the study area (Pamukçu & Yurdakul,
2008) were used as surface and subsurface limits of the boundary conditions on the
140
model. Therefore, by taking into account these knowledge, the models were created
for different temperature values, geological scales and pressure values. The
temperature values which were used in modeling were based on the results of
Dolmaz et al. (2005) and Şalk et al. (2005).
Figure 6.10 The topographic cross-section of the study area. The longitude is 27º and the latitude
changes between 37.2º and 39.7º. BMG; Büyük Menderes graben, KMG; Küçük Menderes graben,
GG; Gediz Graben.
Figure 6.11 Crust-mantle interface values (Pamukçu & Yurdakul, 2008).
In the first application, 200ºK was given at the top of the model and 500ºK was
given at the bottom of the model as temperature values. As a result, the velocity
fields and finite strain fields of deformation which were obtained after 5 Myr, 10Myr
and 15 Myr were shown in the figures from Figure 6.12 to Figure 6.20.
141
Figure 6.12 The temperature distributions on model after 5 Myr for 200ºK-500ºK
Figure 6.13 The finite strain fields on model after 5 Myr for 200ºK-500ºK
142
(a)
(b)
6.14 a) The velocity fields on model after 5 Myr for 200ºK-500ºK b) The velocity fields with vectors
on model after 5 Myr for 200ºK-500ºK
143
Figure 6.15 The temperature distributions on model after 10 Myr for 200ºK-500ºK
Figure 6.16 The finite strain fields on model after 10 Myr for 200ºK-500ºK
144
(a)
(b)
Figure 6.17 a) The velocity fields on model after 10 Myr for 200ºK-500ºK b) The velocity fields with
vectors on model after 10 Myr for 200ºK-500ºK
145
Figure 6.18 The temperature distributions on model after 15 Myr for 200ºK-500ºK
Figure 6.19 The finite strain fields on model after 15 Myr for 200ºK-500ºK
146
(a)
(b)
Figure 6.20 a) The velocity fields on model after 15 Myr for 200ºK-500ºK b) The velocity fields with
vectors on model after 15 Myr for 200ºK-500ºK
It was seen that the finite strain and velocity fields of deformation increased by
increasing geologic time from 5 Myr to 15 Myr. Especially, the collapse and lifting
on the bottom increased on center of the weak zone. It was noticed that the model
deformations are too high after 10 Myr and 15 Myr for 200ºK-500ºK. Therefore, the
software was run for only 5 Myr for higher temperature applications.
147
In the second application, 273ºK was given at the top of the model and 773ºK was
given at the bottom of the model as temperature values. As a result, the velocity
fields and finite strain fields of deformation which were obtained after 5 Myr were
shown in Figure 6.21, 6.22 and 6.23.
Figure 6.21 The temperature distributions on model after 5 Myr for 273ºK-773ºK
Figure 6.22 The finite strain fields on model after 5 Myr for 273ºK-773ºK
148
(a)
(b)
Figure 6.23 a) The velocity fields on model after 5 Myr for 273ºK-773ºK b) The velocity fields with
vectors on model after 5 Myr for 273ºK-773ºK
If these deformed models (for 273ºK-773ºK) showed in Figure 6.22 and 6.23 were
compared with the results for 200ºK-500ºK (Figure 6.13 and 6.14 ) it was noticed
that the finite strain and velocity fields of deformations were looking similar. In the
other words, the deformation didn't increased by increasing the bottom temperature
from 500ºK to 773ºK.
In the third application, 273ºK was given at the top of the model and 900ºK was
given at the bottom of the model as temperature values. As a result, the velocity
149
fields and finite strain fields of deformation which were obtained after 5 Myr were
shown in Figure 6.24, 6.25 and 6.26.
Figure 6.24 The temperature distributions on model after 5 Myr for 273ºK-900ºK
Figure 6.25 The finite strain fields on model after 5 Myr for 273ºK-900ºK
150
(a)
(b)
Figure 6.26 a) The velocity fields on model after 5 Myr for 273ºK-900ºK b) The velocity fields with
vectors on model after 5 Myr for 273ºK-900ºK
In the forth application, 273ºK was given at the top of the model and 1400ºK was
given at the bottom of the model as temperature values. As a result, the velocity
fields and finite strain fields of deformation which were obtained after 5 Myr were
shown in Figure 6.27, 6.28 and 6.29.
151
Figure 6.27 The temperature distributions on model after 5 Myr for 273ºK-1400ºK
Figure 6.28 The finite strain fields on model after 5 Myr for 273ºK-1400ºK
152
(a)
(b)
Figure 6.29 a) The velocity fields on model after 5 Myr for 273ºK-1400ºK b) The velocity fields with
vectors on model after 5 Myr for 273ºK-1400ºK
If the results were compared according to different temperature values, it was
noticed that from the figures (Figure 6.22-6.23, Figure 6.25-6.26, Figure 6.28-6.29)
the finite strain fields enlarged on N-S direction (x-axis) along depth by increasing
the temperature of Moho from 500 ºK to 1400ºK. On the other hand, the velocity
values decreased and the velocity vectors directions changed by increasing the
temperature.
153
In the previous applications, the pressure value was 0.e25 Pa for all different
temperature models. For investigating the deformation changes with decreasing the
pressure values, the pressure was decreased to 0.e125 Pa for the model which had
273ºK-900ºK (Figure 6.30, 6.31).
Figure 6.30 The finite strain fields on model after 5 Myr for 273ºK-900ºK with 0.e125 Pa
Figure 6.31 The velocity fields on model after 5 Myr for 273ºK-900ºK with 0.e125 Pa
If the velocity fields of the model with 273ºK-900ºK (Figure 6.26a) and 0.e25 Pa
compared with the model with 273ºK-900ºK and 0.e125 Pa (Figure 6.31), it was
154
noticed that the velocity began to decreasing from the center of the deformed area to
the borders along to the x-direction by decreasing the pressure. At the same time, the
finite strain fields were larger at 0.e25 Pa (Figure 6.25) than at 0.e125 Pa (Figure
6.30).
At all modeling results at the deformed area, there were high deformation, low
magnitudes of GPS velocities relative to Anatolian block solution, low the Curie
depth points and high heat flow values (Dolmaz et al., 2005), high pressure values,
low gravity anomalies, less earthquakes, shallow crustal structure (Zhu et al, 2006;
Pamukçu & Yurdakul, 2008), Moho ondulations (Çifçi et al., 2011) and lots of
geothermal areas.
155
CHAPTER SEVEN
CONCLUSIONS
Western Anatolia is one of the most tectonically active and rapidly deforming
regions of continental crust in the world. Due to the important case of Western
Anatolia, examining the kinematic mechanism of study area using GPS and gravity
measurements is the objective of this study.
For this purpose as the first step of the application sections, the GPS stations of
the TURDEP and CORS-TR projects which were obtained between the years 2009-
2011 and General Command of Mapping stations which were obtained 2000, 2001,
2004 and 2005 were processed relative to Eurasia fixed frame and additionally,
Anatolian and Aegean block fixed frames by using GAMIT/GLOBK software. In
Eurasia fixed frame solutions, the velocity magnitudes of the stations seemed similar
with each other and approximately 20-25 mm/yr for all stations. The obtained
velocities from this study and the velocities of previous study which were obtained
by McClusky et al., (2000) and TUBITAK project No:108Y285 were plotted
together for examining the velocity changes of the study area during the years. It can
be said that there was no big change from 1997 until 2011 on the directions and
magnitudes of the velocities. According to differences on velocity directions of the
stations, the study area was separated to four regions. Generally, it was pointed out
that the velocity directions of the stations rotated from west to southwest direction
from North to South. The Anatolian Block and Aegean block solutions were obtained
relative to the Euler vectors (Reilinger et al., 2006) for stations of TURDEP and CORS-
TR project for investigating the regional deformation and found that the velocity
magnitudes were between approximately 3-15 mm/ yr. In Anatolian block solutions,
the stations were grouped as 3 regions and 2 lines according to the velocity
directions. In Aegean block solutions, it was pointed out that the velocities of
southern stations were slower relative to the northern stations. It was noticed that the
velocity directions of CESM (Çeşme) and MUGL (Muğla) were different from the
other stations. BALK (Balıkesir) and HARC (Harmancık, Bursa) moved together
156
with the other stations. Additionally, the velocity of KRPT (Karpuzlu, Aydın) station
was very slow relative to other solutions.
As the second step of the application sections, the vertical components of GPS
and microgravity data were compared to investigating vertical mass changing on 6
points; Akhisar (AKHT), Bademli (BDMT), Borlu (BORT), Karacasu (KRCT), Çal
(CALT) and Eşme (ESMT) where obtained two data set on the same point
simultaneously. According to the relationship between GPS and microgravity data,
the deformation were interpreted with considering the earthquake distributions and
topography changes on station areas. For AKHT, BDMT and KRCT, it can be said
that there were not an expected relation between two data set. In AKHT, there was
high seismic activity so; this high seismicity may be the reason of lack of expected
relation between GPS and gravity data and irrelevance on equilibration mechanism
of surface and subsurface structures. According to seismicity, while the northern side
of the KRCT station has high seismic activity, the southern side has low seismic
activity relative to the northern side; oppositely, while the southern side of the CALT
station has high seismic activity, the northern side has low seismic activity relative to
the other side. Therefore, it can be said that KRCT and CALT stations were located
on a boundary. There were positive relations for BORT, CALT and ESMT between
two data set. It means that the surface loadings and subsurface loadings moved at the
same direction. It can be said that there were crustal problems on these station points.
There were geothermal sources near to BORT, BDMT, CALT and ESMT stations,
therefore it can be suggested that the geothermal sources cause the irrelevant on
equilibration mechanism of surface and subsurface structures and low seismic
activity in the station points.
As the third step of the application sections, on the northern normal fault of Gediz
Graben and southern normal fault of Büyük Menderes graben, GPS velocities of the
stations which were located surroundings of these fault were processed relatively
each other by GAMIT/GLOBK software. For northern normal fault of Gediz Graben
according to observed and modeled GPS velocities it can be said that BORT (Borlu,
Manisa) and TRGT (Turgutlu, Manisa) stations were coherent with the N-S
157
directional extension system. On the other hand, SALH (Salihli, Manisa) was not
moving properly with extension system. It was thought that SALH was affected by
both faults. In the next step, the coulomb stress changes were calculated for the
depths of 4 km and 6 km and for the depth range between 0-4 km and 0-6 km.
Consequently, it can be said that the stress area has regional effects for the depth
range between 0-4 km. The stress area (deformed area) had regional effects of total
deeper depth than 4 km. For southern Normal fault of Büyük Menderes Graben,
according to observed GPS velocities, it can be said that KRPT, CALT, BDMT and
KRCT were moving coherently with the main N-S extensional system. AYD1
(Aydın) was moving differently from the other stations, but its velocity was in the
error ellipse. The location of the AYD1 where was very near to the fault may be the
reason of this problem. DENI (Denizli) was found as stabile relative to opposite side
stations. While the observed and modeled GPS velocities for KRPT, BDMT and
KRCT were fitted, for CALT were not. As the next step, the coulomb stress changes
were calculated for the depths of 3 km and 5 km and additionally for the depth range
between 0-3 km and 0-5 km. Consequently, it can be said that Büyük Menderes
graben was affected by stress area up to 3 km. At the depth deeper than 3 km, the
stress area (deformed area) had total regional effects.
Additionally, for investigating the relative movements of the stations for different
directions some processing were done. Firstly, KIKA, AKHT and TRGT were
chosen left side stations and DEIR, BORT, USAK and ESMT were chosen as right
side stations. It was noticed that the velocity directions of DEIR and BORT were
different from ESMT and USAK. Then, DEIR and BORT were moved from the
processing stations and the stations were processed again. It was seen that after
moving DEIR and BORT, the same group stations ESMT and USAK did not
affected but in opposite group stations KIKA, AKHT and TRGT were affected.
Then, DEIR and BORT were added to left station group. It was found that the
velocity directions of DEIR and BORT were different from the same group stations.
Consequently, it can be said that DEIR and BORT were located in a different
structures from the surrounding stations. In other step, same application was done for
the stations near to Büyük Menderes Graben. It was noticed that BDMT, AYD1 and
158
KRPT were moving to South, on the other hand, KRCT, DENI and CALT were
moving to North. Consequently, for the relative applications it can be pointed out
that there may be a zone at N-S direction between the left and right stations.
At the last step of this study, Western Anatolia was modeled by finite element
modeling method for investigating the deformation changes by ADELI software. In
the modeling as the boundary conditions, the south border of Menderes Extensional
Metamorphic Complex (MEMC) at south side and the North Anatolian Fault zone at
north side were chosen. The continental crust was modeled up to 30 km. The
modeled was separated to 3 layers at z-direction. In the first application, 200ºK and
500ºK were given to the top and bottom of the model, respectively. It was seen that
the finite strain and velocity fields of deformation increased by increasing geologic
time from 5 Myr to 15 Myr. Especially, the collapse and lifting on the bottom
increased on center of the weak zone. It was noticed that the model deformations
were too high after 10 Myr and 15 Myr for 200ºK-500ºK. Therefore, the software
was run for only 5 Myr for higher temperature applications. In the second
application, 273ºK and 773ºK were given to the top and bottom of the model,
respectively. If the deformed models (for 273ºK-773ºK) were compared with the
results for 200ºK-500ºK, it was noticed that the finite strain and velocity fields of
deformations were looking similar. In the other words, the deformation didn't
increase by increasing the bottom temperature from 500ºK to 773ºK. In the third
application, 273ºK and 900ºK and in the forth application, 273ºK and 1400ºK were
given to the top and bottom of the model, respectively. As a result, it was noticed that
the finite strain fields enlarged on N-S direction along depth by increasing the
temperature of Moho from 500 ºK to 1400ºK. The velocity values decreased and the
velocity vectors directions changed by increasing the temperature. For investigating
the deformation changes with decreasing the pressure values, the pressure was
decreased to 0.e125 Pa for the model which had 273ºK-900ºK. It was found that the
velocity was decreasing from the center of the deformed area to the borders along to
the x-direction by decreasing the pressure and the finite strain fields were larger at
0.e25 Pa than at 0.e125 Pa. Consequently, the obtained model by ADELI software
159
which has 273ºK -1400ºK temperature, 0.e25 Pa pressure for 5 My is determined
coherent with Anatolian block solutions.
If the deformation models obtained by ADELI were compared with the results of
GPS and microgravity data (discussed in Chapter 4), it was noticed that all of the
stations (Figure 4.1) were located on the deformed area.
As suggestion for the numerical modeling step, different temperature and
different pressure values can be tested for interpreting the deformation in details.
The all results of this study were discussed with seismological and geological data
in related chapters.
160
REFERENCES
Aki, K., & Richards, P. G. (1980). Quantitative Seismology, theory and methods.
Volume I & Volume II: San Francisco: Freeman.
Ashtray (nd). Retrieved January 15, 2014, from
http://ashtray.jz.gts.cz/~smsti/SurveyingCourse/chapter01/.
Battaglia, M., Segall, P., & Roberts, C. (2003). The mechanics of unrest at Long
Valley caldera, California. 2. Constraining the nature of the source using
geodetic and micro-gravity data. Journal of Volcanology and Geothermal
Research, 127, 219-245.
Bozkurt, E. (2000). Timing of extension on the Büyük Menderes Graben, Western
Turkey and its tectonic implications. In: Bozkurt, E. Winchester, J.A. & Piper
J.A.D. (eds), Tectonics and Magmatism in Turkey and the Surrounding Area.
Journal of Geological Society of London, 173, 385−403.
Bozkurt, E. (2001). Neotectonics of Turkey—a synthesis. Geodinamica Acta, 14, 3–
30.
Bozkurt, E. (2003). Origin of NE-trending basins in western Turkey. Geodinamica
Acta, 16, 61–81.
Bozkurt, E., & Sözbilir, H. (2004). Tectonic evolution of the Gediz Graben: Field
evidence for an episodic, two extension in western Turkey. Geological
Magazine, 141, 63–79.
Bozkurt, E., & Park, R.G. (1994). Southern Menderes Massif-an incipient
Metamorphic Core Complex in Western Anatolia, Turkey. Journal of
Geological Society of London, 151, 213–216.
Brun, J.P., & Faccenna, C. (2008). Exhumation of high-pressure rocks driven by
slab rollback. Earth and Planetary Science Letters, 272, 1–7.
161
Brun, J.P., & Sokoutis, D. (2012). 45 m.y. of Aegean crust and mantle flow driven
by trench retreat. Geological Society of America, 38, 815–818.
Butler, K.D. (1984). Microgravimetric and gravity gradient techniques for
detection of subsurface cavities. Geophysics, 49,1084-1096.
Byerlee, J.D. (1978). Friction of rocks. Pure and Applied Geophysics, 116, 615-626.
Cannon, M. E., Schwarz, K. P., & Wong, R. V. C. (1986). Kinematic positioning
with GPS and analysis of road test. Proceeding Fourth International Geodetic
Symposium On Satellite Positioning. Austin, Texas, 28 April-2 May.
Carbone, D., Budetta, G., & Greco, F. (2003). Possible mechanisms of magma
redistribution under Mt Etna during the 1994–1999 period detected through
microgravity measurements. Geophysical Journal International, 153, 187–200
Catlos, E.J., & Çemen, İ. (2005). Monazite ages and rapid exhumation of the
Menderes Massif, western Turkey. International Journal of Earth Sciences, 94,
204–217.
Chandrupatla, T.R., & Belegundu, A.D (2002). Introduction to finite element in
engineering (4th ed.) New Jersay: Pearson Education.
Chery, J., & Hassani, R. (2002). ADELI user’s guide: A 2D and 3D finite element
software for thermomechanical modeling of geological deformation.
Colorado University (nd). Retrieved January 15, 2014, from
http://www.colorado.edu/geography/gcraft/notes/gps/gps.html
Curnier, A. (1993). Méthode numériques en mécanique du solide. Lausanne:
Polytechniques et Universitaires Romandes Press.
Çelik, C. T. (1998). Crustal deformation monitoring by the Kalman filter method.
Ph.D. Thesis, University of Nottingham, Institute. of Engineering Surveying and
Space Geodesy, England.
162
Çemen, İ., Göncüoğlu, C., & Dirik, K. (1999). Structural evolution of the Tuzgölü
Basin in Central Anatolia, Turkey. Journal of Geology, 107, 693–706.
Çemen, İ., Catlos, E.J., Göğüş, O., & Özerdem, C. (2006). Postcollisional
extensional tectonics and exhumation of the Menderes Massif in Western
Anatolia extended terrane, Turkey. Geological Society of America Special
Publication, 409, 353–379.
Çifçi, G., Pamukçu, O., Çoruh, C., Çopur, S., & Sözbilir, H. (2011). Shallow and
deep structure of a supradetachment basin based on geological, conventional
deep seismic reflection sections and gravity data in the Buyuk Menderes
Graben, western Anatolia. Surveys in Geophysics, 32, 271-290.
Çiftçi, N.B., & Bozkurt, E. (2009). Pattern of normal faulting in the Gediz Graben,
SW Turkey. Tectonophysics, 473, 234–260.
Çiftçi, N.B., & Bozkurt, E. (2010). Structural evolution of the Gediz Graben, SW
Turkey: temporal and spatial variation of the graben basin. Basin Research, 22,
846–873.
Demir, C. (1999). Kuzey Anadolu Fay zonu batı kesiminde yatay yer kabuğu
hareketleri ve gerinim birikiminin araştırılması. Ph.D Thesis, Yıldız Technical
University, Graduate School of Natural and Applied Sciences, Istanbul.
Dewey, J.F., & Şengör, A.M.C. (1979). Aegean and surrounding regions: complex
multiple and continuum tectonics in a convergent zone. Geological Society of
America Bulletin 90, 84–92.
Dhatt, G., & Thouzot G. (1981). Une présentation de la méthode des eléments
finis (1st ed.). Paris: Maloine. Paris.
Dinter, D.A., & Royden, L. (1993). Late Cenozoic extension in northeastern
Greece: Strymon Valley detachment system and Rhodope metamorphic core
complex. Geology, 21, 45–48.
163
Doğan, U. (2002). 17 Ağustos 1999 Izmit depreminden kaynaklanan
deformasyonların kinematik modellerle araştırılması. Ph.D Thesis, Yıldız
Technical University, Graduate School of Natural and Applied Sciences, Istanbul.
Dolmaz, M .N., Hisarlı, Z.M., Ustaömer, T., & Orbay, N. ( 2005). Curie point depths
based on spectrum analysis of aeromagnetic data, West Anatolian extensional
province, Turkey. Pure and Applied Geophysics 162, 571-590.
Donellana, A., Hager, B., King R. W., & T. Herring (1993). Geodetic measurement
of deformation in the Ventura Basin Region, Southern California. Journal of
Geophysical Research, 98, 21727-21739.
Dong, D., Herring, T.A., & King, R.W. (1998). Estimating regional deformation
from a combination of space and terrestrial geodetic data. Journal of
Geodynamics, 72, 200-211.
Emre, T. (1996). Gediz grabeninin jeolojisi ve tektoniği (Geology and tectonics of
the Gediz graben). Turkish Journal of Earth Science, 5, 171–185.
Environmental (nd). Retrieved January 15, 2014, from http://www.environmental-
studies.de/Precision_Farming/GPS_E/5E.html.
Ergintav, S., Doğan, U., Gerstenecker, C., Çakmak, R., Belgen, A., Demirel, H.,
et. al (2007). A snapshot (2003-2005) of the 3D postseismic deformation for the
1999, Mw = 7.4 Izmit earthquake in the Marmara Region, Turkey, by first
results of joint gravity and GPS monitoring. Journal of Geodynamics, 44, 1-18
Erkül, F., Helvacı, C., & Sözbilir, H. (2005). Stratigraphy and geochronology of
the early miocene volcanic units in the Bigadiç borate basin, Western Turkey.
Turkish Journal of Earth Science, 14, 227–253.
Ersoy, E.Y., Helvacı, C., & Palmer, M.R. (2011). Stratigraphic, structural and
geochemical features of the NE-SW-trending Neogene volcano-sedimentary
basins in western Anatolia: implications for associations of supradetachment
164
and transtensional strike-slip basin formation in extensional tectonic setting.
Journal of Asian Earth Science, 41,159–183.
Ersoy, E.Y., Çemen, İ., Helvacı, C., & Billor, Z. (2014). Tectonostratigraphy of
the Neogene basins inWestern Turkey: Implications for tectonic evolution of
the Aegean Extended Region. Tectonophysics, doi: 10.1016/j.tecto.2014.09.002
Eyidoğan, H., & Jackson, J.A. (1985). A seismological study of normal faulting in
the Demirci, Alaşehir and Gediz earthquake of-1970 in western Turkey:
implications for the nature and geometry of deformation in the continental
crust. Geophysics Journal of Royal Astronomy Society, 81, 569–607.
Feigl, K.L., Agnew, D.C., Bock, Y., Dong, D., Donnellan, A., Hager, B., et al.
(1993). Space geodetic measurement of crustal deformation in central and
southern California. Journal of Geophysical Research, 98, 21677-21712.
Geuzaine, C., & Remacle, J.-F. (2009). Gmsh: a three-dimensional finite element
mesh generator with built-in pre- and post-processing facilities. International
Journal for Numerical Methods in Engineering, 79(11), 1309-1331.
Gessner, K., Gallardo, L.A., Markwitz, V., Ring, U., & Thomson, S.N. (2013).
What caused the denudation of the Menderes Massif: Review of crustal
evolution, lithosphere structure, and dynamic topography in southwest Turkey.
Gondwana Research, 24, 243–274.
Gleason, G. C., & Tullis, J. (1995). A flow law for dislocation creep of quartz
aggregates determined with the molten salt cell. Tectonophysics, 247, 1 –23.
Glodny, J., & Hetzel, R. (2007). Precise U-Pb ages of syn-extensional Miocene
intrusions in the central Menderes Massif, Western Turkey. Geological
Magazine, 144, 235–246.
Görür, N., Şengör, A.M.C., Sakınç, M., Tüysüz, O., Akkök, R., Yiğitbaş, E., et al.
(1995). Rift formation in the Gökova region, southwest Anatolia: implications
for the opening of the Aegean Sea. Geological Magazine, 132, 637–650.
165
Gürer Ö.F., Sarica-Filoreau, N., Özburan, M., Sangu, E., & Doğan, B. (2009).
Progressive development of the Büyük Menderes Graben based on new data,
western Turkey. Geological Magazine, 146, 652–673.
Hassani, R. (1994). Modélisation numérique de la déformation des systèmes
géologiques. Ph.D thesis, Université Montpellier II, Montpellier.
Hassani, R., Jongmans, D., & Chéry, J. (1997). Study of plate deformation and
stresses in subduction processes using two-dimensional numerical models.
Journal of Geophysical Research, 102, 17951- 17965.
Herring, T. A., King, R.W., & McClusky, S.C. (2010a). GAMIT reference manual:
GPS analysis at MIT, Release 10.4: MIT, Cambridge.
Herring, T. A., King, R.W., & McClusky, S.C. (2010b). GLOBK global Kalman
filter VLBI and GPS analysis program, Release 10.4: MIT, Cambridge.
Hetzel, R., Ring, U., Akal, C., & Troesch, M. (1995). Miocene NNE-directed
extensional unroofing in the Menderes Massif, southwestern Turkey. Journal of
the Geological Society, London, 152, 639–654.
Huc, M. (1997). Modélisation du cycle sismique par la méthode des éléments finis.
Ph.D. thesis, Université Montpellier II, Montpolier.
Iça, M. (1976). Prospection report of hot- spots in Uşak province. MTA Journal
Report, No: 6038, 20.
Infohost (nd). Retrieved January 15, 2014, from
http://infohost.nmt.edu/~mreece/gps/whatisgps.html
Ioane, D., & Ion, D.A. (2005). 3D crustal gravity modelling of the Romanian
Territory. Journal of Balkan Geophysical Society, 8, 189-198.
Işık, V., & Tekeli, O. (2001). Late orogenic crustal extension in the northern
Menderes Massif (Western Turkey); evidence for metamorphic core complex
formation. International Journal of Earth Science, 89, 757-765.
166
Işık, V., Seyitoğlu, G., & Çemen, İ. (2003). Ductile–brittle transition along the
Alaşehir detachment fault and its structural relationship with the Simav
detachment fault, Menderes Massif, Western Turkey. Tectonophysics, 374, 1–
18.
Işık, V., Tekeli, O., & Seyitoğlu, G. (2004). The 40Ar/39Ar age of extensional
ductile deformation and granitoid intrusion in the northern Menderes core
complex: implications for the initiation of extensional tectonics in western
Turkey. Journal of Asian Earth Sciences, 23, 555–566.
Jackson, J., & McKenzie, D. (1984). Active tectonics of the Alpine-Himalayan
Belt between western Turkey and Pakistan. Geophysics Journal of Royal
Astronomy Society, 77, 185-264.
Jackson, J.A., & McKenzie, D.P. (1988). Rates of active deformation in the
Aegean Sea and surrounding regions. Basin Research, 1, 121–128.
Jaeger, J.C., & Cook, N.G.W. (1976). Fundamentals of rock mechanics (1st ed.).
New York: J.W. Sons.
Jentzsch, G., Punongbayan, R.S., Schreiber, U., Seeber, G., Völksen, C., & Weise,
A. (2001). Mayon volcano, Philippines: change of monitoring strategy after
microgravity and GPS measurements from 1992 to 1996. Journal. of
Volcanology and Geothermal Research, 109, 219-234.
Jolivet, L. & Brun, J. P. (2010). Cenozoic geodynamic evolution of the Aegean.
International Journal of Earth Science, 99, 109–138.
Jolivet, L., Faccenna, C., Huet, B., Labrousse, L., Le Pourhiet, L., Lacombe, O., et
al. (2013). Aegean tectonics: Strain localization, slab tearing and trench retreat.
Tectonophysics, 597–598, 1–33.
Kahveci, M., & Yıldız, F. (2009). GPS/GNSS uydularla konum belirleme
sistemleri, uygulama-teori (4th ed.). Ankara: Nobel.
167
Kahveci, M., Pamukçu, O., Çırmık, Y. A. & Gönenç, T. (2013). Using GPS data
together with geophysical data: A case study from a seismically active region,
Izmir. Recent Advences in Space Technologies (RAST 2013), ISBN:978-1-
4244-9616-7, doi:10.1109/RAST.2013.6581206, 231 – 236.
Kaplan, E. D., & Hegarty, C., J. (2006). Understanding GPS: principles and
applications (2nd ed.). Massachusetts: Artech House.
Karaoğlu, Ö., & Helvacı C. (2012). Structural evolution of the Uşak-Güre
supradetachment basin during Miocene extensional denudation in western
Turkey. Journal of the Geological Society, London, 169, 627–642.
Kaya, O. (1979). The stratigraphy and tectonics of the middle eastern Aegean
depression. Bulletin of the Geological Society of Turkey, 22, 35-58.
Kaya, O., Ünay, E., Göktaş, F., & Saraç, G. (2007). Early Miocene stratigraphy of
Central West Anatolia, Turkey: implications for the tectonic evolution of the
Eastern Aegean area. Geological Journal, 42, 85–109.
Koçyiğit, A., Yusufoğlu, H., & Bozkurt, E. (1999). Evidence from the Gediz
graben for episodic two-stage extension in Western Turkey. Journal of
Geological Society of London, 156, 605–616.
Koçyiğit, A. (2005). The Denizli graben-horst system and the eastern limit of
western Anatolian continental extension: basin fill, structure, deformational
mode, throw amount and episodic evolutionary history, SW Turkey.
Geodinamica Acta, 18/3, 167–208.
King, G.C.P., Stein, R. S., & Lin, J. (1994). Static stress changes and the
triggering of earthquakes. Bulletin of Seismological Society of America, 84,
935-953.
King, R.W., & Bock, Y. (2009). Documentation for the GAMIT analysis software,
Release 10.3: MIT, Cambridge.
168
King, R. W., Collins, J., Masters, E. M., Rizos, C., & Stolz, A. (1985). Surveying
with GPS, monograph No. 9, School of Surveying, University of New South
Wales, Sydney.
Le Pichon, X. & Angelier, J. (1981). The Aegean Sea. Philosophical Transactions
of the Royal Society, London Serial A 300, 357–372.
Le Pichon, X., Chamot-Rooke, C., Lallemant, S., Noomen, R., & Veis, G. (1995).
Geodetic determination of the kinematics of Central Greece with respect to
Europe: implications for Eastern Mediterranean tectonics. Journal of
Geophysical Research, 100, 12675–12690.
Leroy, Y., & Ortiz, M. (1989). Finite element analysis of strain localization in
frictional materials. International Journal of Numerical Analysis Methods in
Geomechanics, 13, 53-74.
Leick, A (2004). GPS satellite surveying (3rd ed.) NJ: John Wiley & Sons, Inc.
Lin, J., & Stein, R.S. (2004). Stress triggering in thrust and subduction
earthquakes and stres interaction between the southern San Andreas and nearby
thrust and strike-slip faults. Journal of Geophysical Research, 109, B02303,
doi:10.1029/2003JB002607.
Lips, A.L.W., Cassard, D., Sözbilir, H., Yılmaz, H., & Wijbrans, J.R. (2001).
Multistage exhumation of the Menderes Massif, Western Anatolia (Turkey).
International Journal of Earth Science, 89, 781–792
Locata (nd). Retrieved September 15, 2014, from
http://www.locata.com/applications-of-gps/civilian-applications/.
Lu, G., & Lachapelle, G. (1994). Realibility analysis for kinematic GPS position and
velocity estimation. International Symposium on Kinematic System in Geodesy,
Geomatics and Navigation, KIS 94, Banff, Canada.
169
Maggi, A., Jackson, J.A., McKenzie, D., & Priestley, K. (2000). Earthquake focal
depths, effective elastic thickness and the strength of the continental
lithosphere. Geology, 28, 495-498.
McClusky, S., Balassanian, S., Barka, A., Demir, C., Ergintav, S., Georgiev, I. et al.
(2000). Global Positioning System constraints on plate kinematics and dynamics
in the eastern Mediterranean and Caucasus. Journal of Geophysical Research-
Solid Earth, 105, B3, 5695-5719.
McKenzie, D.P. (1978). Active tectonics of the Alpine–Himalayan belt: the
Aegean Sea and surrounding regions. Geophysics Journal of Royal Astronomy
Society, 55, 217–254.
Meulenkamp, J.E., Van der Zwaan, G.J., & Van Wamel, W.A. (1994). On Late
Miocene to Recent vertical motions in the Cretan segment of the Helennic arc.
Tectonophysics, 234, 53–72.
Montenbruck, O., & Gill, E. (2000). Satellite orbits : models, methods and
applications (1st ed.). New York: Springer.
Moreland K. (2013). The ParaView Tutorial, Version 4.0., Technical Report
SAND 2013-6883P, Sandia National Laboratories.
Mineral Research & Exploration General Directorate (MTA) (2005). Inventory of
Geothermal Sources in Turkey. (Inventory Series-201) Ankara.
Nwcg (nd). Retrieved September 20, 2014, from
http://www.nwcg.gov/pms/pubs/475/PMS475_chap5.pdf
Okada, Y. (1992). Internal deformation due to shear and tensile faults in a half-
space. Bulletin of the Seismological Society of America, 82, 1018-1040.
Okay, A.İ., & Tüysüz, O. (1999). Tethyan Sutures of northern Turkey. In: Durand,
B., Jolivet, L., Hovarth, F., and Séranne, M. (Eds.), The Mediterranean Basins:
170
Tertiary Extension within the Alpine Orogen. Journal of Geological Society of
London, 156, 475–515.
Oral, B. (1994). Global Positioning System (GPS) measurements in Turkey (1988-
1992): Kinematics of the Africa-Arabia-Eurasia Plate collision zone, Ph.D.
Thesis, MIT, Cambridge.
Oral, M. B., Reilinger, R. E., Toksöz, M. N., King, R. W., Barka, A. A., Kınık, İ.,
et al. (1995). Global positioning system offers evidence of plate motions in
eastern Mediterranean. EOS Transaction, 76, 9.
Owen, D. R. J., & Hinton, E. (1980). Finite elements in plasticity: theory and
practice (1st ed.). Swansea : Pineridge.
Öner, Z., & Dilek, Y. (2013). Supradetachment basin evolution during continental
extension: The Aegean province of western Anatolia, Turkey. Geological
Society of America Bulletin, 123, 2115–2141.
Özkaymak, Ç., Sözbilir, H., & Uzel, B. (2013). Neogene–Quaternary evolution of
the Manisa Basin: Evidence for variation in the stress pattern of the Izmir-
Balıkesir Transfer Zone, western Anatolia. Journal of Geodynamics, 65, 117-135.
Pamukçu, O., & Yurdakul, A. (2008). Isostatic compensation in Western Anatolia
with estimate of the effective elastic thickness. Turkish Journal of Earth
Science, 17, 545-557.
Pamukçu, O., Gönenç, T., Uyanık, O., Sözbilir, H., & Çakmak, O. (2014). A
microgravity model for the city of Izmir (western Anatolia) and its tectonic
implementations. Acta Geophysica, 10.2478, s11600-014-0203-z.
Pelzer, H. (1986). Application of Kalman and Wiener-filtering on the determination
of vertical movements. The Symposium on Height Determination on Recent
Vertical Crustal Movements in Western Europe, September, Hannover,
Determination of Heights and Height Changes.
171
Purvis, M., Robertson, A., & Pringle, M. (2005). Ar-40–Ar-39 dating of biotite
and sanidine in tuffaceous sediments and related intrusive rocks: implications
for the early Miocene evolution of the Gördes and Selendi basins, W Turkey.
Geodinamica Acta, 18, 239–253.
Reci, H., Tsokas, G.N., Papazachos, C., & Bushat, S. (2011). Conversion of
Bouguer gravity data to depth, dip and density contrast with complex attributes
analysis technique, in the area of Greece. Romanian Reports in Physics, 63,
302–320.
Reilinger, R., McClusky, S, Vernant, P., Lawrence, S., Ergintav, S., Cakmak, R., et
al. (2006). GPS constraints on continental deformation in the Africa-Arabia-
Eurasia continental collision zone and implications for the dynamics of plate
interactions. Journal of Geophysical Research, 111, No. B5, B05411.
Rimmelé, G., Oberhänsli, R., Goffé, B., Jolivet, L., Candan, O., & Çetinkaplan,
M. (2003). First evidence of high-pressure metamorphism in the 'Cover Series'
of the southern Menderes Massif. Tectonic and metamorphic implications for
the evolution of SW Turkey. Lithos, 71, 19– 46.
Ring, U., Glodny, J., Will, T., & Thomson, S. (2010). The Hellenic Subduction
System: High-Pressure Metamorphism, Exhumation, Normal Faulting, and
Large-Scale Extension. Annual Review of Earth and Planetary Sciences, 38,
45–76.
Salençon, J. (1995). Mécanique du continu. Paris: Ellipses.
Schwards, K. P., Cannon, M. E., & Wong, R.V. C. (1989). Comparison of GPS
kinematic models for determination of position and velocity along trajectory.
Manuscripta Geodaetica, 14, 345-353.
Seyitoğlu, G., & Scott, B.C. (1992). Late Cenozoic volcanic evolution of the
northeastern Aegean region. Journal of Volcano and Geothermal Research, 54,
157–176.
172
Seyitoğlu, G., Scott, B.C., & Rundle, C.C. (1992). Timing of Cenozoic extensional
tectonics in west Turkey. Journal of the Geological Society, 149, 533–538.
Sözbilir, H. (2001). Extensional tectonics and the geometry of related macroscopic
structures: field evidence from the Gediz detachment, western Turkey. Turkish
Journal of Earth Sciences, 10, 51–67.
Sözbilir, H. (2002). Geometry and origin of folding in the Neogene sediments of
the Gediz Graben, western Anatolia, Turkey. Geodinamica Acta, 15, 277–288.
Sözbilir, H., & Emre, T. (1996). Supradetachment basin and rift basin developed
during the neotectonic evolution of the Menderes Massif. In: 49th Geological
Congress of Turkey Abstracts, Ankara, 30–31.
Sözbilir, H., İnci, U., Erkül, F., & Sümer, Ö. (2003). An active intermittent
transform zone accomodating N-S extension in western Anatolia and its
relation to the North Anatolian Fault System. In International Workshop on the
North Anatolian, East Anatolian and Dead Sea Fault Systems. Middle East
Technical University, Cultural Convention Center: Ankara, Turkey, Abstracts;
87.
Sözbilir, H., Sarı, B., Uzel, B., Sümer, Ö., & Akkiraz, S. (2011). Tectonic
implications of transtensional supradetachment basin development in an
extension-parallel transfer zone: the Kocacay Basin, western Anatolia, Turkey.
Basin Research, 23, 423–448.
Spakman, W., Wortel, M.R.J., & Vlaar, N.J. (1988). The Hellenic Subduction
Zone: a tomographic image and its geodynamic implications. Geophysical
Research Letters, 15, 60-63.
Sümer, Ö., Inci, U., & Sözbilir, H. (2013). Tectonic evolution of the Söke Basin:
Extension dominated transtensional basin formation in western part of the
Büyük Menderes Graben, Western Anatolia, Turkey. Journal of Geodynamics,
65, 148– 175.
173
Şalk, M., Pamukçu, O., & Kaftan, İ. (2005). Determination of the curie point depth
and heat flow from magsat data of Western Anatolia. Journal of the Balkan
Geophysical Society, 8, 149-160.
Şen, Ş., & Seyitoğlu, G. (2009). Magnetostratigraphy of early–middle Miocene
deposits from east–west trending Alaşehir and Büyük Menderes grabens in
western Turkey, and its tectonic implications. Geological Society of London,
Special Publications, 311, 321–342.
Şengör, A.M.C., White, G., & Dewey, J.F. (1979). Tectonic evolution of the Bitlis
Suture, southeastern Turkey: implications for the tectonics of the Eastern
Mediterranean Rapp. Comm. International Mer Méditerranee, 25/26. 95–97.
Şengör, A.M.C. (1980). Mesozoic-Cenozoic tectonic evolution of Anatolia and
surrounding regions. Bulletin Bureau de Recherches Géologiques et Minieres,
France, 115, 1–137.
Şengör, A.M.C., & Yılmaz, Y. (1981). Tethyan evolution of Turkey: A plate
tectonic approach. Tectonophysics, 75, 181–241.
Şengör, A.M.C., Görür, N., & Şaroğlu, F. (1985). Strike-slip faulting and related
basin formation in zones of tectonic escape: Turkey as a case study. In: Biddle,
K.T. , Christie- Blick, N. (eds), Strike-slip Faulting and Basin Formation and
Sedimentation. Society of Economic Paleontologists and Mineralogists Special
Publication, 37, 227–264.
Şengör, A.M.C. (1987). Cross-faults and differential stretching of hanging walls in
regions of low-angle normal faulting: examples from western Turkey, in:
Coward M.P., Dewey J.F., Hancock P.L. (Eds.), Continental Extensional
Tectonics. Geological Society Special Publication, 28, 575–589.
Şimşek, Ş., & Eşder, T. (1981). Geological and Geothermal facilities of Denizli-
Kızıldere-Tekkehamam-Tosunlar, Buldan, Yenice regions. Journal of MTA,
report No 7846, 86, Ankara.
174
Toda, S., Stein, R. S., Richards, Dinger K., & Bozkurt, S. (2005). Forecasting the
evolution of seismicity in southern California: Animations built on earthquake
stress transfer. Journal of Geophysical Research, 110, B05S16,
doi:10.1029/2004JB003415.
Toda, S., Stein, R. S., Sevilgen, V., & Lin, J. (2011). Coulomb 3.3 Grafic-rich
deformation and stress-change software for earthquake, tectonic and volcano
research and teaching User Guide : USGS, USA.
Turcotte, D. L. & Schubert, G. (2002). Geodynamics (2nd ed.) NY: Cambridge
University Press.
Uzel, B. & Sözbilir, H. (2008). A First Record of a Strike-slip Basin in Western
Anatolia and Its Tectonic Implication: The Cumaovası Basin. Turkish Journal
of Earth Science, 17, 559–591.
Uzel, B., Sözbilir, H., Özkaymak Ç., Kaymakçı, N., & Langereis, C.G. (2013).
Structural evidence for strike-slip deformation in the Izmir–Balıkesir transfer
zone and consequences for late Cenozoic evolution of western Anatolia
(Turkey). Journal of Geodynamics 65, 94-116.
Ünver, M. (1994). Düşey yöndeki yerkabuğu deformasyonlarının kinematik model ile
belirlenmesi. Ph.D. Thesis, Karadeniz Technical University, Institute of Natural
Sciences, Trabzon.
Van Hinsbergen, D.J.J., Hafkenscheid, E., Spakman, W., Meulenkamp, J.E., &
Wortel, R. (2005). Nappe stacking resulting from subduction of oceanic and
continental lithosphere below Greece. Geology, 33, 325–328.
Van Hinsbergen, D.J.J., Dekkers, M.J., Bozkurt, E., & Koopman, M. (2010).
Exhumation with a twist: Paleomagnetic constraints on the evolution of the
Menderes metamorphic core complex, western Turkey. Tectonics, 29, TC3009.
Vernant, P. (2003). Cinématique actuelle et dynamique de l’Iran: GPS et
modélisation numérique, Ph.D. Thèse, Université de Montpellier II, Montpellier.
175
Watts, A.B. (2001). Isostasy and flexure of the lithosphere. England: Cambridge
University Press, 87–283.
Wessel, P. & Smith, W.H.F. (1998). New, improved version of the generic
mapping tools released. American Geosciences Union, 79, 579.
Xu, G. (2007). GPS: Theory, algorithms and applications (2nd ed.). NY: Springer.
Yılmaz, Y., Genç, Ş.C., Gürer, F., Bozcu, M., Yılmaz, K., Karacık, et al. (2000).
When did the Western Anatolian grabens begin to develop? In: Bozkurt, E.
Winchester, J.A. & Piper J.A.D. (eds), Tectonics and Magmatism in Turkey and
the Surrounding Area. Journal of Geological Society of London, 173, 131–162.
Yurdakul, A. (2007). İzostatik yanıt fonksiyonları ile litosfer yapılarının
incelenmesi. M.sc. Thesis, Dokuz Eylül Univeristy, The Graduate School of
Natural an Applied Sciences, Izmir.
Zeeuw-van Dalfsen, E. Hazel, R., Williams-Jones, G., Sturkell, E. &
Sigmundsson, F. (2006). Integration of micro-gravity and geodetic data to
constrain shallow system mass changes at Krafla Volcano, N Iceland. Bulletin
of Volcanology, 68, 420–431.
Zhu, L., Mitchell, B.J., Akyol, N., Cemen, İ. & Kekovali, K. (2006). Crustal
thickness variations in the Aegean Region and its implications for the extension
of continental crust. Journal of Geophysical Research 111, doi:
10.1029/2005JB003770.
Zienkiewicz, O. (1977). The finite element method. NY: McGraw-Hill.
176