PROBABILISTIC SEISMIC HAZARD ASSESSMENT IN WESTERN HIMALAYA

Abstract

Western Himalaya (Latitude 32.30-36.30 N and Longitude 73.50-80.50 E) is located in the North East part of India. In this region, there many active faults are present. Due to these active faults, Western Himalayas is an earthquake-prone region. The highest earthquake in the Western Himalayas is Mw 7.8 in Kanga on 4th April 1905 and Muzaffarabad, Pakistan has also faced a Mw 7.6 magnitude. Using the Gumbel method, the Gumbel parameters are also calculated, and the yearly expected number, return period, probability of occurrence, and probability of recurrence for different time periods are reported. This study also calculates seismic hazards by the probabilistic seismic hazard analysis (PSHA) using Crisis 2015 software. For this purpose whole area has been divided in to three zones namely the Karakorum fault zone, Kishtwar fault zone, and mantle fault zone the on basis seismo tectonic and geomorphic areas for calculation of seismic hazard, earthquake catalogues 1900 to 2021 are prepared and its homogeneity and completeness are checked. The a & b values are found out by the G-R relationship, and peak ground accelerations are calculated for different periods e.g., 225yrs, 475yrs, and 2475yrs for 20%, 10%, And 2% exceedance of probabilities, respectively.