2016年8月24日意大利佩鲁贾MW 6.2级地震同震位移场估计和震源滑动模型反演

利用改进的自动经验基线校正方法SMBLOC,对2016年8月24日意大利佩鲁贾MW 6.2级地震震中周围约60 km内的近场强震记录进行基线校正并尝试给出同震位移场,与GPS观测结果进行对比分析,分别独立和联合两种资料反演震源滑动模型,并根据震源模型进一步给出全空间预测位移场分布.研究结果表明:(1)两种不同的资料给出的水平位移场幅值均为cm级,且均表明断层的错动以正断为主.(2)两种同震位移场分别独立和联合反演所得的震源静态滑动范围基本一致,最大滑动均发生在震中东北侧,强震模型表现出明显的双事件特征,较大滑动分布在震中东北侧和东南侧,GPS模型在震中东南侧的滑动相对较小,其双事件特征不明显.两种模型的最大滑动量分别为0.96 m和0.86 m,较为一致,反演的矩震级均在MW 6.3左右.(3)根据震源滑动模型计算所得的佩鲁贾地震全空间预测的水平同震位移场中最大位移分布区域与震后报告中受灾严重的地区基本一致.表明在一定的条件下,利用SMBLOC方法解算震级较小的MW 6.0左右地震强震记录的同震位移场,并反演震源滑动模型具有一定的可行性,且其同震位移场和滑动模型可为震后灾害快速评估、救援力量分配、余震趋势判定等快速应急响应工作提供参考依据.

Slip model and co-seismic displacement field derived from near source strong motion records of the Perugia MW 6.2 earthquake,in Italy on August 24,2016

Using an improved automatic empirical baseline correction method SMBLOC to estimate co-seismic displacement field base on near-field strong motion record within about 60 km around the epicenter of the Perugia MW 6.2 earthquake in Italy on August 24,2016,and compared with the displacement results of GPS observations by the Italian Geophysical and Volcanic Research Institute(INGV).Furthermore,using GPS and strong motion records to independently and jointly invert slip model of this earthquake.Finally according to the slip model,the full spatial coseismic displacement field can be predicted.The two horizontal displacement fields magnitude are cm and all show that fault rupture is mainly normal fault mechanism.The two slip models base on different kinds of data and method are roughly similar not only in range but also in maximum slip,which occurred in the northeast of the epicenter.The slip model derived from strong motion data shows obvious double-event characteristics that the large slip is mainly distributed on the northeast and southeast sides of the epicenter,while the slip model inverted from GPS is relatively small on the southeast side of the epicenter,so it was not obvious double-event characteristics.The peak slip of GPS and strong motion models is 0.86 m and 0.96 m respectively.The moment magnitude is both around MW 6.3.The larger displacement region of the horizontal coseismic displacement field calculated base on the slip model is consistent with the area seriously affected by earthquake.So under certain conditions,the SMBLOC method can be used to estimate the co-seismic displacement field for the earthquake of magnitude about MW 6.0 and invert slip model using its near filed strong motion data,and the coseismic displacement field,and slip model can provide reference for the post earthquake emergency response,such as the assessment of seismic hazard,the distribution of the rescue force and so on.