Deterministic Seismic Hazard Map Using Region-Specific GMPEs of Maharashtra State, India

Abstract

Maharashtra stands out as a crucial state in India, demonstrating significant progress in infrastructural development and industrialization. Several prominent cities, including Mumbai, Pune, Nagpur, etc., are significantly contributing to the Indian economy. Considering the importance of the state, a deterministic seismic hazard analysis is executed to reduce the damages to critical and important structures and fatalities caused due to earthquakes. Past earthquakes data are collected within and around the state to prepare a homogenised earthquake catalogue. Seven seismic zones are prepared using K- mean cluster analysis. Independent earthquake events i.e., mainshocks are identified using four renowned declustering methods. Additionally, with the help of mainshocks from each zone, the maximum observed earthquake magnitude (${{\hat m}_{max}}$) and positive correction factor (Δ) are estimated. By superimposing all the mainshocks (after adding Δ) onto the fault map, the maximum observed possible earthquake magnitude of all faults (${{\hat M}_{max}}$) are assigned to each fault. ${{\hat M}_{max}}$ value is used to estimate surface rupture length (RLD) and consecutively, the maximum magnitude (M_Max) from fault sources are estimated. Three region-specific ground motion prediction equations (GMPEs) are adopted in the logic trees assigning a proper weightage to each GMPE. A seismic hazard contour maps are prepared at bedrock level, C, and D-type soil sites for Maharashtra. In the western part of the study area, the maximum PGA value is found to be 0.58 g, 0.70 g, and 0.33 g at bedrock level, C, and D-type sites, respectively.