earthquake hazard in india and the himalayaold.yessenovfoundation.org/lib/uploads/books/presents/8....

EARTHQUAKE HAZARD

IN INDIA AND THE HIMALAYA

Supriyo Mitra

Department of Earth Sciences

IISER Kolkata Seismological Observatory

Indian Institute of Science Education and Research Kolkata, India

Almaty

N Delhi

Indian

Platform

Kazak

Platform

Tectonic

Setting

India is surrounded by Active Plate Boundaries

Himalayan Collision IBCZ

Figure courtesy Roger Bilham

Continent-Continent Collision: 40-50 mm/yr shortening

0-3 mm/yr

20-30 mm/yr

INDIA

TIBET

Continent-Continent Collision: ~50 mm/yr shortening

Major Plate Boundary Earthquakes

2005 NW Kashmir

1950 Assam

1934 Bihar-Nepal

1905 Kangra

1555 Kashmir

1505 Nepal Figure courtesy Roger Bilham

Bhuj, 2001 Jabalpur, 1997

Shillong, 1897

Latur, 1993

Intra-Plate Earthquakes


Copley et al., JGR 2014

15 m

Width: 20-40 km

Length: 40-50 km

Mw 7.8-8.4

Intra-Plate Earthquakes

Copley et al., JGR 2014

Active Plate Boundary – Deaths from Past Earthquakes – Population Density


Buildings as weapons of Mass Destruction


~ 50 Million


Nearly a sixth of the world’s population live in India

Since 1905 Kangra eq. ~10 fold growth in population (NW India)

Active Plate Boundary – Deaths from Past Earthquakes – Population Density

Bilham & Wallace (2005)

Maximum Credible Earthquake

Urban population and slip

potential in the Himalaya

Nepal 2015

Himalayan Seismic Gaps & Earthquake Potential

Mw ~ 8.9

7.5 < Mw < 8.2

Kashmir

Seismic Gap

Sikkim-Bhutan

Seismic Gap

Staggeringly large population vulnerable to future earthquakes


Step-1: Recognition of the fact that Earthquakes pose a major

threat.

Step-2: Understand that it requires a scientific mission to study

earthquakes and quantify the associated hazard.

Not a prediction problem!

Step-3: Undertake seismological experiments to acquire data.

(and encourage cooperation in data and knowledge sharing!)

Step-4: Develop a scientific workforce to study earthquakes.

(encourage collaborative efforts with countries having significant

know-how)

Step-5: Devise mechanism to educate people about earthquake

preparedness and resilience.

Seismic Hazard in India


threat.




Date Magnitude Deaths Name

4 April 1905 7.5 19,000 Kangra

15 Jan 1934 8.1 10,700 Bihar-Nepal

15 Aug 1950 8.6 3,300 Assam

19 Oct 1991 7.0 2,000 Uttar-Kashi

29 Sep 1993 6.2 9,748 Latur-Killari


threat.




(and encourage cooperation in data and knowledge sharing?)


IMD and NGRI Seismograph Networks in India

National

Geophysical

Research

Institute

Indian

Meteorological

Department

CU-IIA-IITKGP-IISERK Seismograph Networks in India

National

Geophysical

Research

Institute

Indian

Meteorological

Department

CU – IITKGP

- IISERK


threat.







know-how)


Earthquake Faulting

Observed Ground Motion

Earthquake Faulting


5. Predict Ground Motion

1. Velocity Model

2. Characterize Faults

(Location & Mechanism)

3. Attenuation Model

4. Local Site Effects

Velocity Structure of The Himalaya

• Lithospheric shortening by

underthrusting of the Indian plate

> 300 km beneath Eastern Himalaya

~ 500 km beneath NW Himalaya

• Entire crust is Seismogenic (colder than 600°C)

2005

2011

2006

Profile-A Profile-B

Seismic Velocity Structure of India and The Himalaya

Earthquake Faulting



1. Velocity Model






Mega Thrust Earthquakes Along plane of detachment

between mountain belt & underthrust Indian plate

Mega Thrust Earthquakes Along plane of detachment (MHT)

between mountain belt & underthrust Indian plate

Himalayan Seismic Gaps & Earthquake Potential

Mw ~ 8.9

7.5 < Mw < 8.2

Kashmir

Seismic Gap

Sikkim-Bhutan

Seismic Gap


NW Himalaya

Kashmir Earthquake

Kangra Earthquake

Avouac et al. (2006)

Major Indian Earthquakes (since 1900)

Date Magnitude Deaths Name

4 April 1905 7.5 19,000 Kangra

15 Jan 1934 8.1 10,700 Bihar-Nepal

15 Aug 1950 8.6 3,300 Assam

19 Oct 1991 7.0 2,000 Uttar-Kashi

29 Sep 1993 6.2 9,748 Latur-Killari

22 May 1997 6.0 39 Jabalpur

29 Mar 1999 6.8 103 Chamoli

26 Jan 2001 7.6 20,085 Bhuj

08 Oct 2005 7.6 86,000 Kashmir

2005 Kashmir Earthquake • Thrust fault

• NE dipping (29°) fault plane

• Depth ~11 km (MHT)

• Short rise time between 2s & 5s

• Bilateral rupture (vr ~ 2 km/s)

Avouac et al. (2006)

NW Himalaya

Kashmir Earthquake

Kangra Earthquake

2013 Kishtwar Earthquake

• Thrust fault

•NE dipping (26°) fault plane

• Depth ~16 km (MHT)

S. Mitra, Sunil Wanchoo and Priestley, K. (2014) Bull. Seismo. Soc. America, 104 (2), pp 1013-1019.

2013 Kishtwar Earthquake

• Hypocenter: on or above the MHT

• Close to the downdip end of the locked zone (~150 km)

• Spatially marks a zone of strain accumulation

S. Mitra, Sunil Wanchoo and Priestley, K. (2014) Bull. Seismo. Soc. America, 104 (2), pp 1013-1019.

UK-IERI and NERC-IAA

Debarchan Powali, Sharma, Swati, Mitra, S., Wanchoo, S.K., Priestley, K.F. and Gaur, V.K. Lithospheric

Structure and Earthquakes beneath Kashmir Himalaya. Abstract (T21B-4587) AGU Fall Meeting 2014.

Kashmir Himalaya: Lithospheric Structure and Earthquakes



Kashmir Himalaya: Lithospheric Structure and Earthquakes

Receiver Function Piercing Point Map

SW NE

NGRT SMVD UDHM RAMN CHEN WANI BADR PHAG

Moho

40

Moho

55

? MBT MCT

SW-NE Profile: RF Common Conversion Point (CCP) Stack

MHT

25

MHT

8

Indian crust underthrusts J&K Himalaya: base highlighted by large impedance contrast boundary

Crustal Thickness increases from ~40 km (Siwalik Himalaya) to ~55 km (Higher Himalaya) MHT highlighted by a LVL dipping NE: ~8 km (Siwalik Himalaya) to ~25 km (Higher Himalaya)



NGRT SMVD UDHM RAMN CHEN WANI BADR PHAG

Moho

? MBT MCT

SW-NE Profile: RF CCP Stack and Earthquakes

SW NE

The 2013 Kishtwar earthquake occurred at the downdip junction between the MBT and the MHT

Entire crust is seismogenic

Possible Modes of Maximum Slip and Mmax


2015

25 April 2015 Nepal Earthquake and its Aftershocks

• Mainkshock: Mw 7.8 (Gorkha district) Nepal

• Largest earthquake to have occurred in this region in the past 81 years.

• Followed by Mw 7.3 aftershock on 12 May 2015 (eastern edge)

Source Properties of the Mainshock

Mitra, S., H. Paul, A. Kumar, S. K. Singh, S. Dey and D. Powali (2015) The 25 April 2015 Nepal

earthquake and its aftershocks, Current Science, vol. 108, no. 10, pp 19381943, 25, May 2015.

• Mainshock ruptured ~150 x 55 km shallow NE dipping (~5°±3°) fault (MHT)

• Unzipped the frictionally locked downdip segment of the MHT

• Caused the Himalaya to slip SW by 4.8±1.2 m over the Indian plate

NERC-Emergency Grant: Bihar-Nepal BB Experiment

May 2015 onwards

INDIA

NEPAL

University of Cambridge (U.K.) – DMG (Nepal) – IISER Kolkata (India)

June 2015 onwards

Rupture Propagation (source time history) from Array Analysis

Australian

Japanese

European

25 April 2015 Nepal (Gorkha) Earthquake

• Unilateral rupture: W E but with variable vr ~ 2.1 to 3.5 km/s

• Confined to the downdip segment of MHT

Rupture Propagation (source time history) from Array Analysis

Mainshock Source Mechanism: Multiple Sub-Events

0-20s

20-35s

35-50s

50-70s

N~6°

Mw 7.2

WNW~15°

Mw 7.3

N~7°

Mw 7.4

Mw 7.3

Oblique

Strike-Slip

H~15km

Lateral

Ramp

Spatio-Temporal Evolution

MHT

Flat

MHT

Flat

2015 April 25 Gorkha (Nepal) Earthquake and its Aftershocks

Loaded the updip & western segment of the MHT (last great earthquake 1505)

Significantly increased the potential for future great earthquake(s)

2001 Bhuj

1997 Jabalpur

1993 Latur

1897 Shillong

Intra-Plate Earthquakes Away from the plate boundary

within the Indian Platform

• 35 earthquakes (M > 5.5) – MT5

• 7 earthquakes (4.0 < M < 5.0) - LWI

• 15 earthquakes (previous studies)

Intra-Plate Earthquakes: NE India

Seismotectonics: Shillong Plateau, Mikir Hills and Bengal Basin

• Dextral Strike-Slip Earthquakes in the Kopili Fault Zone – extends NW and SE

All earthquakes are in the mid-lower crust

• Thrust earthquakes along northern edge of Shillong Plateau (S dipping reverse fault)


4 January 2016 Manipur Earthquake

53


• Dextral Strike-Slip Earthquakes in the Kopili Fault Zone – extends NW and SE

Mid-lower crustal earthquakes

• Sinistral Strike-Slip Earthquakes in the Bengal Basin (Reactivated Paleo-Rifts)

• Thrust earthquakes along northern edge of Shillong Plateau (S dipping reverse fault)

Michael S. Steckler, Dhiman Ranjan

Mondal, Syed Humayun Akhter4,

Leonardo Seeber, Lujia Feng, Jonathan

Gale, Emma M. Hill and Michael Howe

Deep focus (h>40 km) earthquakes

18 September 2011

Sikkim, India

Mw 6.9

Earthquakes beneath the Himalaya within the underthrust Indian plate

18 September 2011

Sikkim, India

Mw 6.9

2011 Sikkim Earthquake

(1) Mainshock on near vertical

fault, oriented NW-SE oblique

to the Himalayan arc

Himangshu Paul, S Mitra, S.N. Bhattacharya & G. Suresh Geophys. J. Int. (2015) 201, pp 1070–1081.

(2) Rupture initiated at SE end

of the fault and propagated NW

with dextral strike-slip motion

(3) Aftershocks (occurred SE of

mainshock) have predominantly

strike-slip motion


(3) Faulting originated at 53±4 km and ruptured at least 20 km of seismogenic

lower crust (underthrust Indian Plate)

(4) Aftershocks originated between 12 and 50 km depth (within the underthrut

Indian crust) – Entire Crust Seismogenic

(5) Deformation distinct from the

Phodong Earthquake (above MHT)


1992

1991

1980

2011 Sikkim Earthquake

and Aftershocks

Julia Singer, György Hetényi, Tobias Diehl and Eduard H Kissling (2014) Structure of the Orogenic Wedge in the

Bhutan Himalaya: First Results from the GANSSER Seismic Experiment, 2014 AGU Fall Meeting Abstract T21B-4573.

GANSSER Seismic Experiment

Poses a significant Seismic Hazard to the densely populated

Brahmaputra Valley and Shillong Plateau (NE India)

Earthquake Faulting



1. Velocity Model





Attenuation (Q0) map: NE India, Sikkim & Nepal Himalaya

Ray coverage map

Attenuation (Q0) map: NE India, Sikkim & Nepal Himalaya

Q0

Local Site Effects

Future Ground Motion

Earthquake Faulting


1. Velocity Model





threat.







know-how)

Step-5: Devise mechanism to educate people about earthquake

preparedness and resilience.


Moving towards a Resilient Bihar Earthquake Risk Reduction Strategies by

Bihar State Disaster Management Authority (BSDMA)

Anil K. Sinha, IAS (retd.)

Vice Chairman

Bihar State Disaster Management Authority

Government of Bihar (India)

Arial view of Patna (Capital) Source: Google Images

Location of Bihar in India

Acknowledgements

Collaborators

Keith Priestley & Alex Copley (University of Cambridge), V. K. Gaur (CMMACS), S.N.

Bhattacharya (ex-IMD), Kajaljyoti Borah (IISER-K) and S.K. Wanchoo, (SMVDU)

Seismology Group

IISER Kolkata

Data and Funding

IMD, NGRI, IRIS-DMC and GFZ Potsdam for sharing BB, GDSN and INDEPTH data;

SEIS-UK, NERC and DST for funding and Instrument support; IISER Kolkata, University

of Cambridge, IITKGP, UK-IERI, NERC for financial support and research infrastructure

IISER-K Seismology Group

Debarchan Powali, Jashodhara

Choudhury, Swati Sharma, Ajay

Kumar, Siddharth Dey and Shubham

Sharma

Past Members S. Manna, H. Paul,

S. Singh, T. Ajaay, U. Mannu,

Growing Population

Risk

Earthquake Hazard Map

• 1833

• 1934

• 1988

• 2015

• 20__????

Past Earthquakes in Bihar

Flood Hazard Map

Source: DMD, GoB

Drought Hazard Map

Response to Nepal- Bihar Earthquake

Full page Newspaper advertisement in all leading newspapers for schools,

offices & General Pub,lic

Bihar State Disaster Management

Authority

73


Authority

74

Emergency Operation

Centre established at

BSDMA

Training & Capacity Building of Buildings Department in Rapid Assessment


Authority

75

Training & Capacity Building of Urban Development Department in Rapid Assessment


Authority

76

Training & Capacity Building through of all engineers in the field through Video Conferencing


Authority

77

Provided support to IISER Kolkata in Installation of Seismographs


Authority

78

Disaster Risk Reduction

Structural Mitigation/ Risk Reduction

Non-Structural Mitigation/ Risk Reduction

DRR Approach of BSDMA

79

• Policies and Laws,

• Public Awareness &

Education

• Capacity Building & Training

• Promotion of Safe Construction

• Retrofitting

• Policies and Laws related to

Safe Construction

Meetings/ Reviews

– Promoting Safe Construction through organizing

regular Training Programs on Earthquake

resistant design for Engineers & Architects.

– Series of review meetings held with construction

wing of Education & Health department.

– Modifications in the Bihar Urban Development

Act & Building Bye laws.

Structural Mitigation


Authority

80

• A Memorandum of Understanding (MoU) signed between

BSDMA and National Institute of Technology Patna on 24

November 2014 for the establishment of an 'Earthquake

Safety Clinic & Centre' at NIT Patna.

Partnerships & Collaborations


Authority

81

Earthquake Safety Clinic & Centre

(20 January, 2015)

With live size models representing features of safe construction


Authority

82

Earthquake Safety Week

(15th - 16th January, 2015)


Authority

83

Certified Training Program organized

for ~200 participants comprising of

experts: Professional Engineers,

Architects from NDRF, Private

Builders and Govt deptt. on

Earthquake Resistant Construction.

5 Day WORKSHOP on Trainers' Development Programme for Earthquake Resistant Buildings in Bihar.

(27th -31st May, 2015)


Authority

84

District Disaster Management Plan (DDMP) for

all the districts

85

Advisory Committee on Earthquake

(1st Meeting, 20th January, 2015)


Authority

86

Valmiki

Nagar

Siwan

Motihari

Patna

Chhapra

Muzzaffarpur

Saharsa

Madhubani

Samastipur Purnea

Munger

Araria

Sitamarhi

Gaya Jamui

Bihar Seismological Telemetry Network

Existing

Proposed by IMD

Proposed by BSDMA & DST

Chief Minister School Safety Program


Authority

88

Chief Minister School Safety Program

• More than 20 Million Children trained in

Earthquake Safety through mock drills- 2

rounds of such drill had taken place in last

two years.

• 150,000 teachers trained in executing

School Safety Program

• 500 Master Trainers were trained to train

these 150,000 teachers.

Information, Education & Communication (IEC) Materials


Authority

90

Till now more than 50 types of

IEC materials focusing on

various disasters & various

groups have been produced

Challenges

Thus, the growing risk raises the following questions –

• What should be the core indicators of a resilient

city in the context of Bihar?

• Which existing policies, procedures and related

rules (like town planning, building codes,

development plans, land zoning, and such) should

be refined or created a new so as to make cities in

Bihar resilient?

• How and where can cities learn more from those

who have already taken action for building

resilient urban systems?

Challenges

Thus, the growing risk raises the following questions –

• What kind of refinements should be made in the existing systems for civic amenities (like waste management (solid waste, bio-medical & e-waste), water supply, power, safe spaces, and such) to make cities resilient in Bihar?

• What should be the specific short term and long term actions done to support ULBs in making urban areas resilient in Bihar?

Opportunities

• The volume and pace of urban growth

anticipated over the next 10-15 years offers an

opportunity to avoid past development

mistakes and reflect resilience in policy,

planning, design and investment decisions.

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