Seismic hazard assessment studies based on deterministic and probabilistic approaches for the Jammu region, NW Himalayas

The Jammu region is located in the Northwestern Himalayas, which has been hit by moderate to large magnitude earthquakes regularly, including the deadliest 2005 Kashmir earthquake in Muzzafarabad. In this study, deterministic and probabilistic seismic hazard assessment of the Jammu region was carried out based on a logic tree framework. Within a 350-km radius of the Jammu, all potential seismic sources were identified, and an updated earthquake catalogue was prepared, spanning the years 1520 AD to 2020 AD. In DSHA, a hybrid scenario is developed using two independent earthquake scenarios. Three declustering algorithms with four GMPEs for active shallow crustal and Himalayan region clubbed to form a hybrid model for PSHA. Peak ground acceleration and peak spectral acceleration at 0.2 s and 1.0 s were estimated for 2% and 10% probability of exceedance in 50 and 100 years. For rock site conditions, the seismic hazard curves and uniform hazard response spectrum are presented for ten main cities of the Jammu region. This area shows the peak ground acceleration (PGA) variation between 0.08 and 0.66 g with maximum hazard in the southwestern part comprising of districts of Poonch, Rajouri, and Jammu, and parts of Reasi. IS-1893 (2016) suggested 0.24 g for a 2% probability of exceedance in 50 years which is significantly higher than PGA predicted in the present study. The hazard values will be useful for the designing of structural elements of infrastructure projects in this region.