Risk scenario of Himachal Pradesh considering the 1905 Kangra earthquake by using Deterministic approach

Himachal Pradesh is one of the most seismically active regions in India. Consequently, reliable Seismic Hazard Analysis (SHA) is essential for sustaining the infrastructural and economical developments of the region. Deterministic Seismic Hazard Analysis (DSHA) of Himachal Pradesh has been carried out considering the scenario of 1905 Kangra earthquake. The DSHA was based on two different ground motion prediction equations (GMPE's) and the results produced by both equations were compared. The input data comprises of hypothetical magnitude (Mw 8), location of epicenter (Main Boundary Thrust), surface rupture length (200 Km), slip of the fault, Wells and Coppersmith rupture model, attenuation characteristic and focal depth (25 Km). The scenario map was developed using a regular grid of 1 Km x 1 Km by the model summation technique using RISK.iitb.3.0 v software. The hazard analysis shows the Peak Ground Acceleration (PGA) of the order of 0.023g-1.556g and the maximum intensity IX-X covering an area of 1,13,357 sq. km. The earthquake catalogue of the region covering 117 km radius around Himachal Pradesh has also been generated separately after processing collected earthquake data since1554 to 2020 (>4.0 M). Furthermore, a seismic risk map of Himachal Pradesh has been designed by considering four parameters i.e., PGA, Household density, Population density and Seismicity. The results indicate that 48.95% of the area of the state primarily comprising districts of Kangra, Chamba, Lahaul Spiti, Mandi and Kullu is under moderate to high risk.