Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

During the wee hours of October 08, 2005, a devastating shallow focused (16.2 km) earthquake with moment magnitude of Mw 7.7 occurred in the Pakistan’s Kashmir Hazara Region. Its tremors were felt in a radius of over 1000 km with damages taking place in an area of 36000 sq km. More than 0.1 million people died and the rehabilitation of infrastructures damages are estimated to cost around five billion dollars. The Kashmir Hazara terrain is located on the NW margin of lesser Himalaya. The KHS is one of the bold tectonic scars which physically isolate this terrain from rest of the Himalaya. Other major tectonic features sculpturing this terrain in the shape of folds and faults are: Main Mantle Thrust (MMT), Main Boundary Thrust (MBT), Panjal Thrust (PT), Hazara Thrust (HT) and the Indus Valley Faults. All these mega structures are the abode of variable seismicity and generate earthquakes of low to high (damaging) magnitude. The seismic zones of the mega-crustal deformations in the Kashmir Hazara terrain, from where the earthquakes emanate generally lies between 10 – 60 km surface depths. The earthquakes generated at this depth are categorized as shallow and are usually more hazardous. The earthquake resulted from the subduction of Indo-Pakistan plate beneath the Eurasian plate and it ruptured the southwest Jhelum Thrust (JT) fault. The fault was previously inferred to be as active in a region where the river incises directly into the Murree sandstones on the west side of the valley (footwall of JT), while it has abandoned large inset terraces along the east side (hanging wall of JT). The occurrence of Kashmir-Hazara earthquake confirms that the active Jhelum Thrust (JT) and Jhelum Fault (JF), in a region located well north of the Main Himalayan Frontal Thrust, accommodate roughly EW-oriented, present day shortening related to “zipper tectonics” within the part of the Kashmir Hazara Syntaxis (KHS). Maximum Modified Mercalli Intensity was X at Balakot, situated on the hanging wall side of the causative fault and the maximum ground motions in the same area were inferred to be 0.90 ‘g’ from overturned vehicles in the direction parallel to the axis of valley.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

Seismotectonic Contours of Kashmir-Hazara Region and Seismological Aspects of October 08, 2005 Earthquake

San Diego, California

During the wee hours of October 08, 2005, a devastating shallow focused (16.2 km) earthquake with moment magnitude of Mw 7.7 occurred in the Pakistan’s Kashmir Hazara Region. Its tremors were felt in a radius of over 1000 km with damages taking place in an area of 36000 sq km. More than 0.1 million people died and the rehabilitation of infrastructures damages are estimated to cost around five billion dollars. The Kashmir Hazara terrain is located on the NW margin of lesser Himalaya. The KHS is one of the bold tectonic scars which physically isolate this terrain from rest of the Himalaya. Other major tectonic features sculpturing this terrain in the shape of folds and faults are: Main Mantle Thrust (MMT), Main Boundary Thrust (MBT), Panjal Thrust (PT), Hazara Thrust (HT) and the Indus Valley Faults. All these mega structures are the abode of variable seismicity and generate earthquakes of low to high (damaging) magnitude. The seismic zones of the mega-crustal deformations in the Kashmir Hazara terrain, from where the earthquakes emanate generally lies between 10 – 60 km surface depths. The earthquakes generated at this depth are categorized as shallow and are usually more hazardous. The earthquake resulted from the subduction of Indo-Pakistan plate beneath the Eurasian plate and it ruptured the southwest Jhelum Thrust (JT) fault. The fault was previously inferred to be as active in a region where the river incises directly into the Murree sandstones on the west side of the valley (footwall of JT), while it has abandoned large inset terraces along the east side (hanging wall of JT). The occurrence of Kashmir-Hazara earthquake confirms that the active Jhelum Thrust (JT) and Jhelum Fault (JF), in a region located well north of the Main Himalayan Frontal Thrust, accommodate roughly EW-oriented, present day shortening related to “zipper tectonics” within the part of the Kashmir Hazara Syntaxis (KHS). Maximum Modified Mercalli Intensity was X at Balakot, situated on the hanging wall side of the causative fault and the maximum ground motions in the same area were inferred to be 0.90 ‘g’ from overturned vehicles in the direction parallel to the axis of valley.