Probabilistic seismic hazard analysis of Madhya Pradesh (Central India) using alternate source models: a logic tree approach

Abstract

This study presents the macro-level probabilistic seismic hazard analysis (PSHA) of Madhya Pradesh using the classical Cornell-McGuire method. It investigates the seismic hazard of the region using two different source models—one covering seismogenic sources within 200 km (19–28° N and 72–84° E), and another within 300 km (16–32° N and 69–88° E) from the peripheral boundaries of Madhya Pradesh. It also proposes a new hybrid model that combines the above two models using a logic-tree approach and produces hazard maps and response spectra (bedrock level) for the seven smart cities proposed under the Smart City Mission of the Government of India. Finally, the study’s results are compared with the standard recommendations by IS 1893–2016 (Part-1) and National Disaster Management Authority (NDMA 2010). PSHA is performed using an updated earthquake catalog between 1800 and 2020 compiled from various national and international resources. Standardization of catalog is performed in terms of homogenization of magnitudes to moment magnitudes (Mw), zone-wise catalog division, and declustering using Gardner and Knopoff (1974) algorithm. It utilizes the logic tree approach to address the uncertainties associated with source modeling, source characterization, and selection of ground-motion prediction equations (GMPEs). Ground accelerations corresponding to different parts of the study region are calculated by dividing the region into a 0.2° rectangular grid in orthogonal directions. This study presents the PGA maps for the entire region for the return periods of 475 and 2475 years (equivalent to 10% and 2% probability of exceedance in 50 years, respectively) and first-hand response spectra (bedrock level) for the seven smart cities corresponding to spectral accelerations, SA (T), for periods of 0.1 s, 0.2 s, 0.5 s, 1 s and 2 s on stable firm rock site condition (Vs30 as 760 m/sec) based on the 200 km, 300 km, and hybrid source models. The study finds the 200 km source model's results in fair agreement with the national recommendations, whereas the 300 km source model's results higher than the national recommendations. The results from this study shall render a great help to city planners for designing new structures and also in retrofitting the existing structures.