The Saurashtra horst in the Gujarat state is an intraplate region located in the westernmost part of India, bounded by three failed rifts, namely Kachchh, Cambay, and Narmada. The region is prone to swarm type of seismic activity, mostly occurring after an intense summer monsoon. In this study, the focal mechanism of earthquakes occurring in the Saurashtra region has been investigated. The earthquakes are clustered in two groups, one in the northern part near the Jamnagar region and the other in the southern part near the Talala region. The focal mechanism of 29 earthquakes were determined with 16 in the Jamnagar region and 13 in the Talala region. The magnitude range of these earthquakes is 3.1–5.1. It is found that the Jamnagar region located in the northern part is characterized by reverse faulting and the Talala region located in the southern part is characterized by strike-slip faulting. The focal mechanisms obtained are inverted to find out the present-day stress field in the Saurashtra horst. It is observed that the Jamnagar and the Talala regions are dominated by radial compression and transtension regimes, respectively. The source parameters of some of these earthquakes from the strong motion data are also estimated. It is found that the stress drop of earthquakes in this region is in the range 9–69 bars, lower than the adjacent Kachchh rift. The average stress drop of the strike-slip earthquakes is found to be more than the reverse mechanism earthquakes, which agrees with the observation in the adjacent Kachchh rift. It is also observed from the data set that the stress drop of the earthquakes in the Saurashtra is dependent on the earthquake size and independent of the focal depth.
