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Probabilistic Seismic Hazard Analysis of the Shillong Plateau, Northeast India, Using Multiple Source Models and Logic Tree Approach

Description: 

In the present study, we have attempted to estimate the seismic hazard of the Shillong Plateau using Probabilistic Seismic Hazard Analysis (PSHA) by clubbing the up-to-date earthquake catalogue and seismotectonic of the region. An earthquake catalogue for the Shillong Plateau and adjoining region for the period of 825-2024 from various national and international data sources was compiled, homogenized, declustered, and checked for completeness. PSHA of the study region is computed using three distinct types of source models, namely, areal, linear, and gridded sources. The seismicity of the sources is evaluated by the modified Gutenberg-Richter model. Based on the efficacy test, three distinct GMPMs is selected. The logic tree approach is applied to minimize epistemic uncertainty. The probabilistic seismic hazard of the Shillong Plateau (SP) at the bedrock level has been computed in terms of Peak Ground Acceleration (PGA) and Spectral Acceleration (SA) for spectral periods 0.0-2.0 sec and 2%, 5%, 10%, 20%, and 50% probability of exceedance (PoE) in 50 years. Hazard curves and Uniform Hazard Response Spectrum (UHRS) for eleven district headquarters in the Meghalaya state of India are also prepared at bedrock level for 5% damping. PGA for 10% PoE in 50 years ranges from 0.66-1.04, whereas, for 2% PoE in 50 years, it ranges from 1.06-1.66. It can be observed that the seismic hazard is higher in eastern Meghalaya and gradually decreases towards western Meghalaya.

Session: Advancing Time-dependent PSHA and Seismic Risk Assessment: Accounting for Short- to Medium-term Clustering [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Mohd

Student Presenter: Yes

Invited Presentation: 

Poster Number: 76

Authors