ANALYSES OF FOCAL MECHANISM SOLUTIONS OF THEHERAT TRIPLET EARTHQUAKE OF OCTOBER ۷TH, ۲۰۲۳AND ITS LARGE AFTERSHOCKS

On October ۷, ۲۰۲۳ a triple earthquake sequence occurred in the Herat province, westernAfghanistan. The first event with ML ۶.۳ happened at ۰۶:۴۱ (UTC) according to the report ofInternational Institute of Earthquake Engineering and Seismology (IIEES). This event was followedby two other earthquakes at ۰۷:۱۲ and ۰۷:۴۰ (UTC) with ML ۶.۵ and ۶.۲, respectively. Two otherlarge events occurred on October ۱۱th and ۱۵th with ML ۶.۴ and ML ۶.۵, respectively in the sameregion. These earthquakes have been followed by many smaller aftershocks. In this study threecomponentvelocity seismograms recorded by the Iranian National Broadband Seismic Network(INSN) of IIEES and the Iranian Seismological Center (IRSC) from ۷ to ۱۵ October ۲۰۲۳ were used toinvestigate the focal mechanisms of ۱۲ events including the Herat multiple earthquakes and its largeaftershocks using first-motion polarities and waveform inversion techniques. The analyses of thesource mechanisms of the studied events show multiplicity of the activated faults. This confirms thatmany tectonic structures and fault branches intersected and reactivated in a common region betweeneastern Iran and western Afghanistan.

کلیدواژه ها:

West Afghanistan ، Multiple Earthquakes ، Focal Mechanism ، Inversion ، Eastern Iran