SEISMIC HAZARD ASSESSMENT

Abstract

Gumbel extreme value theory has been applied to estimate the probability of occurrence and return period of the largest earthquake in Gujarat region India. The expected extreme based magnitude of 49 year (1965-2013) seismicity data of one year extreme values of earthquake for region have been plotted. The yearly expected number, mean return period and risk for occurrence of earthquake in the consider region have been estimated. The most probable medium size earthquake that may occur in the region are estimated and reported. The result presented in this study is only best long-term estimate subject to the limitation of the earthquake data. Seismic hazard assessment refers to an opinion of ground motion parameters at any site or region. In the present study seismic hazard has been performed for the Gujarat region using the seismicity data provided by IDM, GSI, USGS, ISC, GERI, ISR. Assuming one third of the total fault length as rupture length of MCE, maximum magnitude to each source is assigned. After the judgment of distance of zone of energy release two different attenuation models are used to define peak horizontal acceleration based on shortest distance between sites and sources. It has been seen that among major fault in Gujarat region cambey west fault (CWF) produces maximum acceleration (Ah) using attenuation relationships by SHARMA (2000) equal to 0.1469g and 0.061181g using attenuation relationships Boore, Joynosard and Fumal(1993)