Source Mechanism and Tectonic Analysis of 06 May 2022 Mw 5.4 Khuzdar Earthquake along Western Boundary of the Indian Plate

Abstract On May 06, 2022 an earthquake of M5.4 occurred in NW of Khuzdar (Baluchistan), Pakistan. This event caused damages to infrastructure and collapsed several mud houses, according to local news agencies. On the same day, an earthquake of a similar size (M5.4) which is 230km away from the Khuzdar earthquake occurred in Dalbandin, Baluchistan. Both of these earthquakes were independent and have not appeared to be related with each other. The 2013 Awaran earthquake of magnitude 7.7 has been the largest event within this region, located 70 km away from a recent event. The recent seismicity within the Khuzdar area might be the post viscoelastic relaxation the of Awaran earthquake having the NE-SW nodal plane as the fault plane. To understand the faulting style and tectonic setting, moment tensor inversion was performed using local seismic data. The mechanism of this event was strike-slip (sinisteral faulting style) and associated with Ornach-Nal strike-slip fault. Based on 38 events focal mechanism solutions from the global Harvard Centroid Moment Tensor (CMT) of the Khuzdar region depict NW-SE orientation of SHmax direction. Reduced stress tensors obtained from formal stress inversion are then divided into two subsets (thrust and strike-slip) on basis of their stress homogeneity. The present-day stress state confirms, the oblique convergence of Indian and Arabian Plates beneath Eurasian which is subjected to a transpressional tectonic environment. A lower b-value (0.7) and accelerated earthquake sequence were observed in the Khuzdar region before this event. The spatial distribution of b-value depicts the lowest value in this region, before the occurrence of the Awaran earthquake. Although high differential stress was exhibited in this region but large has not occurred. These stresses were transferred to the western part, where the Awaran earthquake has been occurred.