【摘要】 以2015年4月26日MS7.1余震为经验格林函数事件,利用全国和全球的宽频带记录提取了2015年4月25日尼泊尔MS8.1地震的P波视震源时间函数和Rayleigh波视震源时间函数,并通过联合反演这些视震源时间函数获得了这次地震的时空破裂过程图像.无论是P波视震源时间函数还是Rayleigh波视震源时间函数都呈现出很强的方位依赖性,表明震源断层具有相当的尺度且破裂朝东南方向扩展.时空破裂过程图像清楚地证实了这一特征,并更清晰地显示,破裂几乎是纯粹的单侧破裂,从破裂起始点开始,沿断层面向东南方向扩展~100km,同时沿断层面向深部扩展~80km,形成~125°的破裂优势方向和~5.8m的最大位错.地震的破裂时间历史相对简单,呈非间断性扩展,持续时间约50s.更多还原

【Abstract】 The apparent source time functions(ASTFs)of the Nepal MS8.1earthquake which occurred on April 25 of 2015are retrieved from the P waveform data and the Rayleigh waveform data recorded at the broadband stations across the world and China using the MS7.1aftershock as the empirical Green′s function event,which occurred on April 26 of 2015.And the image of the rupture process of the main-shock is obtained by jointly inverting the P-ASTFs and the RayleighASTFs.The evidential azimuth-dependence appears on both the P-ASTFs and the RayleighASTFs,indicating that the fault is finite in dimension and the direction of the faulting is at southeast.It is confirmed by the image of the tempo-spatial rupture,and the image more clearly shows that the rupture is nearly apurely unilateral one,starting at the initial point,propagating~100km toward southeast and ~80km toward depth on the fault plane,respectively,and resulting in a dominant rupture direction of~125°and a maximal dislocation of ~5.8 m.The rupture time history is relatively simple,suggesting an uninterrupted rupture with a duration time of about 50 s.更多还原