A Seismic History of Crete

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The seismicity in Greece and in the adjacent regions is the highest in the Western Eurasia. One of the most active seismotectonic structures in that region is the Hellenic Arc and Trench (H-AT) system. The island of Crete occupies the central segment of H-AT just to the north of the front where the lithospheric plates of Africa and Eurasia converge and the former bends and subducts beneath the later. Therefore, the shallow and intermediate-depth seismicity in the area of Crete is very high. In addition, these processes produce other important geodynamic phenomena, such as volcanic eruptions along the South Aegean Sea island arc as well as tsunamis.

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  • A Seismic

    Earthquakes and Tsunamis: 2000 BC 2011 AD

    The Hellenic Arc and Trench

    GerasSimos A. Papadopoulos

    Historyof Crete

    National Observatory of Athens

    Ocelotos Publications

  • Earthquakes and Tsunamis: 2000 BC 2011 AD

    The Hellenic Arc and Trench

    GerasSimos A. Papadopoulos

    title A Seismic History of Crete suBtitle Th e Hellenic Arc and Trenchauthor Gerassimos A. Papadopoulos

    PuBlishers sieries Science [5358]0611/03Book desiGn Ocelotos Publications

    Copyright 2011 Gerassimos A. Papadopoulosfirst PuBlished Athens, October 2011

    ISBN 978-960-9499-68-2

    Vatatzi 55 str., 114 73 Athens EL. : 210 6431108E-MAIL: ekdoseis.ocelotos@gmail.com, ocelotos@otenet.gr

    www. ocelotos. gr

    This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licens-ing agreements, no reproduction of any part may take place without the written permission of the author and of Ocelotos Publications.

    pub l i ca t i onsocelotos

  • To the undying memory of Smaroula

    for ever loved, for ever missed

  • ,

    , , .

    , , 172-174

    There is a land in the middle of the dark sea,Crete: beautiful, prolific, surrounded by the sea,

    and there are ninety cities with uncountable people.

    Odyssey, Rapsody T, 172-174

    . .

    , .

    , , 57-60

    .and from underneath Poseidon shook off the immense Earth and the mountains steep tops. And all foothills of Idi were shaken along with the

    many jets of water and the mountains tops,

    and the city of Troyans as well as the boats of the Achaians.

    Iliad, Rapsody Y, 57-60

  • ContentsPreface .......................................................................................................................................................11Why Write a Book about Earthquakes in the Area of Crete? ..................................................11The History of this Book and Some Acknowledgements ........................................................13

    Chapter1 Geodynamics, Seismotectonic Setting and Seismicity .....................................................17Geology ......................................................................................................................................................17Geodynamics ...........................................................................................................................................18Seismicity and Seismic Hazard ..........................................................................................................21Fault-plane Solutions and Stress Field ...........................................................................................22Seismotectonic Imaging .....................................................................................................................23Microearthquakes Associated with Karsts ....................................................................................26Morphogenic Earthquakes and Palaeoseismology ...................................................................27

    Chapter 2Information Sources, Data and Methodology .......................................................................31Pre-historical Period: Before the 6th Century BC .......................................................................31Historical Period: From the 6th Century BC up to the End of the

    19th Century AD ........................................................................................................................31The Unpublished Manuscript of Pavlos Vlastos (1850-1926) .................................................39Coping with Idioms ...............................................................................................................................40Instrumental Period: After 1898 ......................................................................................................40Methodology ...........................................................................................................................................40A New Historical Catalogue ................................................................................................................42

    Chapter 3Key Events and Key Test-Sites........................................................................................................43The Giant Late Bronze Age (LBA) Eruption of Thera Volcano ................................................43Tsunamis Associated with the LBA Eruption ...............................................................................44The Archaeological Site of Gortyn, Central-South Crete .........................................................52The Archaeological Site of Phalasarna, NW Crete: the Key Earthquake and

    Tsunami Events of 66 AD and 365 AD ...............................................................................52The Key Earthquake and Tsunami Event of 1303 .......................................................................61The Earthquake of 1508 .......................................................................................................................61The 1650 Eruption of Columbo, Thera Island Complex ...........................................................61The Earthquake of 1810 ......................................................................................................................63The Earthquake of 1856 .......................................................................................................................63

    Chapter 4Earthquakes and Tsunamis in Minoan and Doric Crete (20th century

    to 2nd century BC) .................................................................................................................64Discovery and Chronology of the Minoan Civilisation ...........................................................64Evidence of Seismic Destruction in Minoan Crete .....................................................................68Association Between Volcanic Eruptions and Intermediate-depth

  • Contents

    10

    Earthquakes: A Geodynamic Scenario ..............................................................................75From the Minoan period to the Roman period ..........................................................................78

    Chapter 5Earthquakes and Tsunamis During the Roman Occupation

    (1st Century BC to 3rd Century AD) ...............................................................................80Short Historical Review ........................................................................................................................80Review of Earthquake Events in the Roman Period ..................................................................80

    Chapter 6Earthquakes and Tsunamis During the Byzantine Period

    (330-824 and 961-1211) and the Arabic Occupation (824-961) ......................90Short Historical Review ........................................................................................................................90Review of Earthquake Events in the Byzantine period ............................................................90How Often Will the 365 Earthquake Repeat? ........................................................................... 106

    Chapter 7Earthquakes and Tsunamis During the Venetian Occupation (1211-1669).............. 115Short Historical Review ..................................................................................................................... 115Review of Earthquake Events in the Venetian Period ............................................................ 116

    Chapter 8Earthquakes and Tsunamis During the Turkish Occupation (1669-1898) ............... 184Short Historical Review ..................................................................................................................... 184Review of Earthquake Events in the Ottoman Period ........................................................... 185

    Chapter 9Earthquakes and Tsunamis During the Period of the Autonomy

    of Crete The Primitive Instrumental Period (1899-1913) ............................. 303Short Historical Review ..................................................................................................................... 303Review of Earthquake Events in the Primitive Instrumental Period ................................ 304

    Chapter 10Earthquakes and Tsunamis in Crete in the Early Instrumental Period

    (1914-1963) ........................................................................................................................... 342Short Historical Review ..................................................................................................................... 342Review of Earthquake Events in the Early Instrumental Period ......................................... 342

    Chapter 11Earthquakes and Tsunamis in Crete in the Modern Instrumental

    Period (1964-2011) ............................................................................................................. 354References ........................................................................................................................................... 364Sources ................................................................................................................................................... 390Abbreviations ...................................................................................................................................... 392Appendix I: Empirical Relationships ........................................................................................... 393Appendix II: The New Tsunami Intensity Scale ........................................................................ 395Appendix III: List of earthquake events ..................................................................................... 398

  • 11

    Preface

    Why Write a Book about Earthquakes in the Area of Crete?

    Seismicity in Greece and in the adjacent regions is the highest in all of Western Eurasia. One of the most active seismotectonic structures in that region is the Hellenic Arc and Trench (H-AT) system. The island of Crete, which is part of the sedimentary arc of the H-AT, is situated at the central segment of the H-AT just to the north of the plate margin where the lithospheric plates of Africa and Eurasia converge. Since this is where the former bends and subducts beneath the latter, the shallow and intermediate-depth seismicity in and around Crete is very high. In addition, these processes produce other important geody-namic phenomena, such as volcanic eruptions and tsunamis along the South Aegean Sea island arc.

    Cretan civilisation was among the earliest to develop, so the record of earthquakes is ex-tensive. Around 2000 BC, an important development emerged from the Minoan civili-sation: the construction of large buildings called palaces. Such palaces were construct-ed mainly in Knossos, Phaistos, Ayia Triada and Malia, and the impact of earthquakes on these monumental buildings and other Minoan settlements was charted throughout this Bronze Age civilisation, from 2000 BC up to about 1200 BC.

    Data sets of historical and instrumental earthquakes indicate that this area is prone to shallow and intermediate-depth earthquakes with maximum magnitudes up to about 8 and over. The AD 365 and 1303 earthquakes, two of the largest ever reported in the Euro-pean-Mediterranean region, occurred along the H-AT system. The first, with an estimated magnitude of 8.3, very likely ruptured the segment to the west of Crete, while the sec-ond, with an estimated magnitude of 8.0, ruptured the segment to the east of the island. Both events were catastrophic and the destruction was completed by the large tsunamis caused by each earthquake. Those two tsunamis were the largest historically documented in the European-Mediterranean region, given that they inundated not only coastal zones

  • PrefaCe

    12

    of Crete, but also propagated to remote places of the Eastern Mediterranean Basin caus-ing extensive damage.

    There is no active volcanism on the island of Crete. However, eruptions occurring in the volcanic complex of Thera, which is situated about 120 km to the north of Crete, have had significant impact on the island. The impact of the giant, caldera forming Late Bronze Age or Minoan eruption (17th century BC) has long been a source of discussion. There is no doubt that, among other phenomena associated with the eruption, a large tsunami was triggered that flooded the northern coast of Crete, as is evidenced by tsunami sediment deposits, and further verified by numerical simulations of the wave. Historical documen-tation of the extra-caldera eruption of the submarine volcanic edifice of Columbos, in AD 1650, indicated that a large tsunami was produced again, which propagated well into the South Aegean Sea and inundated the northern coast of Crete. And once again the same results were yielded following the tsunami produced by the large tectonic earthquake of 9 July 1956, which ruptured part of the Cyclades island complex in the South Aegean Sea.

    The very rich seismic history of the area of Crete has thus far been documented by his-torical sources as well as instrumental records. However, this historical documentation is incomplete and several earthquake incidents remained unknown thus far. In addition, some vital events of the instrumental era of seismicity had not been well-studied. There-fore, the first objective of this book is to illustrate the need to review further the historical seismicity of Crete.

    It is worth noting that new knowledge about the historical earthquake phenomena in the area of Crete was accumulated from field geological and archaeological observations and analytical laboratory results, e.g., for dating purposes, as well as from numerical modeling and other studies of tsunamis. Until now, such observations and techniques were not in-tegrated in a unified methodological approach as a supplement to historical and instru-mental documentation. This unique methodology in data integration has provided the second objective for writing this book. In fact, for each of the seismic events examined, particularly the major ones, all available information was taken into account with the aim to understand the event better: documentary sources, damage to buildings and other structures, geological and archaeological field observations, instrumental records, pictori-cal material, influence on social, political and cultural life.

    The third reason that prompted the decision to write this book is actually based on three key events that have taken place in the area of Crete: the Late Bronge Age (LBA) or Mi-noan eruption of Thera, and its associated large tsunami; and the big tsunamigenic earth-quakes of AD 365 and 1303. The volcano of Thera, a...

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