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Site-characterization Vis-À-vis Surface-consistent Probabilistic Seismic Hazard From Kashmir Himalaya to Northwest Himalaya

Description: 

Abstract: The incidences of earthquakes in Kashmir Himalaya to Northwest Himalaya are broadly associated with presence of active faults. The study region falls under Seismic Zone IV and V according to Bureau of Indian Standards, and has been struck by several devastating earthquakes viz. 1905 Kangra earthquake of MW 7.8, 1975 Kinnaur earthquake of MW 6.8, 1991 Uttarkashi earthquake of MW 6.8 and 2005 Kashmir earthquake of MW 7.6 causing widespread damage and destruction in the terrain. The region has undergone unprecedented development and population growth, emphasizing the importance of Probabilistic Seismic Hazard Assessment (PSHA) to ensure safe and secure progress in such a seismically vulnerable region. This study performs a PSHA on firm rock conditions, incorporating both tectonic and polygonal sources at the hypocentral depth ranges of 0-25km, 25-70km, 70-180km, and 180-300km. The analysis utilizes and Next Generation Attenuation models within a logic tree framework estimated Peak Ground Acceleration (PGA) ranges from 0.21g to 0.95g for 475years of return period, emphasizing a site-specific study for seismic site characterization. Seismic site classification has been done based on an enriched geophysical, geotechnical database and topographic gradient derived shear wave velocity categorizing the terrain into 11 Site Classes from E to A. Site response analysis has been performed to derive absolute site amplification, which is used to calculate the surface-consistent PGA varying from 0.29g to 1.78g. The Liquefaction Potential and Landslide Susceptibility Index serve as secondary hazards, complementing both geohazard and seismic hazard frameworks to enable a comprehensive seismic hazard microzonation of the capital cities of Srinagar and Shimla. As an implication of the seismic hazard, Damage Potential Modeling for the cities have been performed. Thus the results of this investigation are expected to play vital roles in the earthquake prone county to pre disaster mitigation and post disaster management.
Keyword: Probabilistic Seismic Hazard Assessment; Site Class; Microzonation; Damage Potential Modeling.

Session: Earthquake-triggered Ground Failure: Data, Hazards, Impacts and Models [Poster]

Type: Poster

Date: 4/17/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Amrendra Pratap

Student Presenter: Yes

Invited Presentation: 

Poster Number: 2

Authors