2010年青海玉树M_s 7.1地震近断层地面运动估计  

Estimation of the fault-near ground motion of the 2010 Yushu,Qinghai,M_s7.1 earthquake

作　　者：许力生[1] 邸海滨[1] 冯万鹏[1] 李春来[1] 

机构地区：[1]中国地震局地球物理研究所,北京100081

出　　处：《地球物理学报》2010年第6期1366-1373,共8页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(40874026);地震行业基金(200708031)资助

摘　　要：2010年4月14日在我国青海省玉树藏族自治州发生了M_s 7.1级地震.地震给当地群众的生命财产带来巨大损失,其中最严重的破坏发生在震中东南的玉树县城.我们利用反演远场地震波形得到的震源破裂模型和Crust2.0提供的当地的地壳模型,计算了近断层地面运动(速度场和位移场),再现了地震发生时当地的地面运动图像.根据这个图像,震源的单侧破裂过程导致了明显的多普勒效应.地震波自震中向四周扩散开去,但沿着断层向东南方向传播的地震波的幅度更大、波峰更密.玉树县城恰好位于地面静态位移较大的区域,也位于较强烈的位移波和速度波穿越的地带.与实际的地面运动相比,虽然我们的计算还不够精确,但无容置疑,破裂过程导致的多普勒效应是玉树县城遭受严重破坏的主要原因.On April 14th, 2010, an Ms7.1 earthquake occurred in Yushu Tibetan Autonomous State, Qinghai province, China. It resulted in a great loss of life and property, and especially, the Yushu, a city southeastern to the epicenter, was most seriously damaged. We calculated the ground motion, including displacement and velocity, near the causative fault using the dynamic model of rupture process from the inversion of teleseismic waveform data and the crust model of Crust2.0, reconstructing an image of the fault-near ground motion at the time of quaking. The image shows that there appeared the evident Doppler＇s effect, generated by the unilateral rupture process of the source. Seismic waves radiated out wards from the epicenter, but those propagating toward southeast along the fault had much larger amplitudes, and were much more crowded. The Yushu city happens to lie on not only where static displacement was larger also where the stronger velocity waves and displacement waves ran through. There should be no doubt that the Doppler＇s effect caused by the unilateral rupture process was the main reason why the most disastrous damage happened in the Yushu city, in spite the estimated ground motion was not accurate enough compared with the real one.

关 键 词：玉树MS7.1地震 破裂过程 多普勒效应 地面运动 地震灾害 

分 类 号：P315[天文地球—地震学]