【摘要】 2024年4月3日中国台湾东部花莲海域发生M_S7.3地震,该地震位于欧亚板块与菲律宾海板块强烈碰撞的缝合带上,对该地震序列震源参数的研究将有助于认识台湾花莲地区纵谷断裂的地震活动特征。本文利用宽频带数字地震资料,对该地震序列开展震源机制解、地震辐射能量、持续时间和库仑应力的测定工作。研究结果表明:(1)花莲海域主震是一次逆冲型为主的地震事件,4次M_S≥6.0余震的震源机制也均为逆冲型为主的事件,与震源区主要断裂带构造性质一致;(2)主震和较大余震辐射能量结果表明,主震属于能量效率偏高的事件,而4次余震均低于主震的能量释放效率;(3)库仑应力分布结果显示,主震的发生使震中投影附近区域出现较大范围的应力卸载,与位错集中区域较为吻合。更多还原

【Abstract】 On April 3,2024,a magnitude 7.3 earthquake occurred in the Hualien Sea area,Eastern Taiwan,China,according to the China Earthquake Networks Center.The earthquake took place along the suture zone where the Eurasian Plate converges with the Philippine Sea Plate.Studying the source parameters of this earthquake sequence provides valuable insights into the seismic characteristics of the Zonggu fault in the Hualien region,Taiwan.Using broadband digital seismic data,we determined the focal mechanism solutions,seismic radiation energy,event duration,and Coulomb stress for the entire seismic sequence.The results are as follows:(1)The main earthquake,located near the coast of Hualien,is a thrust-type event,and the four aftershocks with M_S≥6.0 are also thrust-type,consistent with the tectonic properties of the main fault zone in the focal region.(2)The radiation energy analysis reveals that the main shock is a high-energy event,while the aftershocks release energy less efficiently than the main event.(3)The Coulomb stress distribution shows that the main earthquake caused significant stress unloading in the area near the epicenter projection,with the stress redistribution aligning closely with the observed dislocation concentration.更多还原