An Investigation of 2013 M_w 7.7 Awaran Earthquake, Pakistan

Abstract

Abstract. Earthquake is a major disaster responsible for vast losses both life and infrastructure. Pakistan is one of the highly earthquake prone areas in Asia. The present study is carried out to investigate the dynamics of disastrous Awaran earthquake. The 2013 Mw 7.7 Awaran earthquake and its Mw 6.8 aftershock caused numerous loss of lives and vast infrastructure damages. The earthquake triggered along Hoshab fault rupturing 230 km of the fault. The rupture propagated at 3 Km/s on average and was concentrated in top 10 km with no major displacement in the underlying decollement. The rupture released a cumulative moment of 5.4 x 1020 Nm. This study reveals that although Hoshab fault originated as thrust fault, the slip was purely strike slip during the earthquake and that the rigid block rotation of southeastern Makran is responsible for the Awaran earthquake. The study concludes that the earthquake significantly increased the coulomb stress on Makran mega thrust and strike slip faults in Chaman fault system, hence increasing the risk of a major seismic event. Therefore, in order to prevent major loss of lives and infrastructure damages; designing of new building codes, reassessing the seismic hazard of the region and marking of hidden faults is of utmost importance.