摘要
On December 18,2023,a Mw6.1 earthquake struck Jishishan County,Gansu Province,China,marking the most significant earthquake in the northeastern edge of the Tibetan Plateau since 2000.Given its proximate to the Loess Plateau,which is extremely susceptible to geohazards,this earthquake raises awareness about the seismic hazard of several mega-cities such as Xi'an in Northwest China.In this paper,we inferred that the rupture occurred on an east-dipping backthrust,resulting from the regional E-W contraction tectonic setting.Our dynamic model through teleseismic waves and static model through radar displacement measurements together reveal a unilateral,along-strike rupture,encountering a slip barrier at one side of the main slip patch causing a cluster of aftershocks.We also identified a high-dip structure,which is an early-stage backthrust fault whose dip becomes increasingly high due to regional compressional tectonism.Apart from the loaded fault segments,particularly on the fault linkage,which necessitate continuous examination,a detailed seismic hazard assessment of the west Qinling and Daotanghe-Linxia fault system identifies a seismic gap between Weiyuan and Dingxi with the potential for a Mw7.5 earthquake.Collectively,these findings provide valuable insights into the seismic behavior of the seismogenic fault as well as guidance on hazard mitigation in its surrounding fault systems.
基金
funded by the National Natural Science Foundation of China(No.42377159)
the Shaanxi Province Science and Technology Innovation Team(No.2021TD-51)
the Shaanxi Province Geoscience Big Data and Geohazard Prevention Innovation Team(2022)
the Fundamental Research Funds for the Central Universities,CHD(No.300102263401)。
