Comprehensive seismic hazard assessment for Guwahati City, Northeast India: Insights from probabilistic and deterministic seismic hazard analysis

Abstract

This paper presents a comprehensive seismic hazard assessment for Guwahati city, located in the northeast region of India. The earthquake data considered for the study is from 1762 to 2020, which was sourced from the published data of various seismological agencies. The fault information comprises of the latest studies and Seismotectonic Atlas (SEISAT) data. The density of earthquakes close to the faults was used to define the fault zones. The G-R relationship was utilized to calculate the seismicity parameters of the identified faults. We have used PSHA and DSHA to estimate the ground motion parameters such as peak ground acceleration and spectral acceleration at various probabilities of exceedance to calculate the level of seismic hazard. The results indicate that the seismic hazard in Guwahati is moderate to high, with several active faults in the vicinity and a high potential for strong ground motions. This study includes identifying the controlling source for Guwahati and plotting the seismic hazard curve and uniform hazard spectra for various probabilities of exceedance, which will give a basic idea of the seismic hazard of the city. The findings of this study can be used as a basis for earthquake risk reduction and mitigation strategies in Guwahati.