【摘要】 基于美国流动台网的三分量远震P波资料,利用相对反投影方法,对2010年2月27日Mw 8.8智利地震的破裂过程成像。根据美国地质调查局(USGS)给出的震源参数及源区地质资料,设定一个小倾角断层面。将远震P波反投影至该断层面上,获取震源破裂过程。结果表明,智利地震破裂由3个子事件组成,破裂长度至少为513 km,宽度至少为100 km。破裂从震中开始向北方和南方两个方向双侧扩展,但北侧的破裂明显强于南侧。北侧的破裂长度约为340 km,破裂持续时间约125 s,破裂速度约为2.87 km/s;而南侧破裂长度约为173 km,破裂持续时间约99 s,破裂速度约为1.84 km/s。另外,北侧两个子事件的能量释放高峰分别出现在破裂开始之后16 s和79 s,与初始破裂点的距离分别为75 km和230 km。南侧子事件的能量释放高峰出现时刻为80 s,与初始破裂点的距离为145 km。智利地震在破裂过程中可能受到了破裂区域的障碍体影响。更多还原

【Abstract】 The Mw 8.8 Chilean earthquake of 27 February 2010 was the greatest Chilean earthquake since 1960.The back projection method based on the non-plane wave assumption is used to image the rupture process on an oblique fault plane with three-component broadband seismograms recorded by the U.S.Array Transportable Network.The results show that the Chilean earthquake was composed of three sub-events,and ruptured with at least 513 km in length and 100 km in width.Moreover,the rupture bilaterally extended northwards and southwards after the initiation of the earthquake and was dominated by the northern branch.The northern branch of the earthquake ruptured over a length of about 340 km in 125 s,which indicates that its average rupture velocity was about 2.87 km/s.Meanwhile,the southern branch had a rupture length of 173 km in 99 s,which means the southern average rupture velocity was about 1.84 km/s.In addition,after the onset of the quake,the energy peaks of two sub-events in the northern branch occurred at 16 and 79 s,which were 75 and 230 km away from the epicenter.The energy peak of the sub-event in the southern branch appeared at 80 s and located about 145 km away from the epicenter.更多还原