Development of fault and seismicity maps for the state of Goa, India.

Abstract

Earthquake magnitude recurrence relations are developed for the State of Goa on the west coast of Peninsular India. The Seismic influence zone for the study area of Goa was considered as 350 km from the state boundary. The zone comprises mainly of Koyna on the North, Latur region on the North – east and the Karnataka region on the west. The earthquake data consisted of both historical and instrumental earthquakes from the year 1767 to 2013. Foreshocks and aftershocks were removed from the catalogue and the de-clustered catalogue was tested for completeness by Cumulative VIsual (CUVI) method. The spatial and temporal distribution of the earthquake events in the Seismic influence zone of the study area was obtained. The recurrence relation established for the State of Goa was log λm = 6.41 – 0.91Mw. The Fault map and the Seismo-tectonic map of Goa were developed. To ascertain the extent of influence of the past earthquakes in the seismic influence zone on the study region of Goa, intensity based maps were developed for 5 past earthquake events. It was found that a maximum Intensity VII on MSK scale could be felt in the State of Goa in the case of re-occurrence of past earthquake events at or near the same location.