Seismicity analysis of selected faults in Makran Southern Pakistan

Abstract

This study was focused on evaluation of seismicity yield of key faults guarding the terrestrial Makran region (Balochistan and Iran) using updated datasets. The Makran onshore region is bounded by paramount strike-slip faults (Chaman fault, Ghazaband fault, Ornach-Nal fault and Minab fault). We have compiled the earthquake’s catalog and performed iterative processes for declustering of independent main shocks, estimation of magnitude completeness and b-values. The main shocks of disastrous earthquakes, e.g., Mw 7.7 Quetta (1935) and Mw 7.7 Awaran (2013), have epicenters along the Ghazaband fault and splay of Chaman fault, respectively. The earthquake source parameters such as moment magnitude, focal depth, focal mechanism, and epicenter location was utilized in mapping and seismicity evaluation of the faults. The focal mechanism solution was derived to determine the fault mechanics in generating the Mw > 5.0 events along these faults. This study helped us to compare the seismological profiles of each boundary fault and present the seismological information including the characteristics of events on/along fault, estimation of re-occurrence period, corresponding b-value, and hazard potential of the of the key faults. Since our study is based on recent dataset, i.e., inclusion of 2013 Mw 7.7 Awaran earthquake, the estimated results could help in better planning against the earthquake hazard in near-field cities & coastal towns of southern Pakistan.