A Model of the Seismic Rupture Surface of the January 22, 2024 Aykol, China, Earthquake Based on SAR Interferometry Data

Abstract

In this study we present the model of the rupture surface of the M_W = 7.0 Aykol earthquake, which occurred on the border of PRC and Kyrgyzstan on January 22, 2024, as well as the model of the rupture surface of its strongest aftershock on January 29, 2024, with magnitude M_W = 5.7 based on satellite radar interferometry data. We derived displacement fields of the Earth’s surface in the satellite line of sight for these events using Sentinel-1A imagery and resolved the inverse problem of estimating displacement fields on the rupture surfaces. The resulting rupture surface models reveal the presence of fault systems dipping towards one another. The fault plane of the main event is a thrust with left-lateral shear component dipping to the northwest. During the development of the aftershock process, a backthrust dipping to the southeast developed in the frontal region, displacing the western portion of the frontal thrust formed during the main shock. Such fault dynamics is a result of the complex structure of the fault zones in the studied region. Backthrusts in this area had been mapped during previous field works.