Probabilistic Assessment of Seismic Hazard for Uttarakhand State of India

Abstract

Abstract Uttarakhand state of India, being located in the seismically active Himalayan mountain range, is highly prone to seismic hazards. This study presents assessment of seismic hazard of Uttarakhand through probabilistic approach. For conducting this study, a homogenous earthquake catalogue for moment magnitude during the period 1953 - 2020 with magnitude range of 2.0 - 6.9 consisting of 522 events was used. Various geological structures viz. folds, faults and lineament as well as thrust, have been identified in the associated regions. The state was divided into several grid points and the seismic hazard was evaluated for each of the grid points through probabilistic method. Finally, based on the analysis results, bedrock level hazard maps were developed for the state for contingency level earthquake (CLE) and maximum credible earthquake (MCE). The estimated peak ground acceleration (PGA) of the state is in the range of 0.16g-0.52g for CLE and the PGA varies for 0.20g-0.61g for MCE level earthquake. Main Central Thrust (MCT), Sunder Nagar fault and Ropar fault were observed to be more hazardous in the northern region of the state.