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2008年5月12日,四川省汶川县发生了毁灭性大地震.地震发生于一段曾被认为存在中度地震危害性的断层上,在震前几乎没有观测到前兆现象.考虑到四川省现有地震台的覆盖面,应急地震学本来可以有效地避免地震带来的一些破坏,并对震后应急反应方面给予帮助.从回顾的角度上看,文章证明仅仅用两个三分量地震台站就足够在10s内对地震的震中位置给出误差范围在20km的定位.从P波初至的前4s信号,可以估计地震的震级为7级;更准确的震级估计则可以利用耗时2min的Pnl波形模拟来完成,此时在500km外的地震台站刚刚接收到S波.利用震后2h内发生的5级以上余震,破裂区域能被很好的显示出来.在几个小时内,更详细的破裂过程和有限断层模型能通过分析远震体波记录来得到,并可随时用来计算地面强震动,从而在没有实时强震记录可用的情况下为救援工作提供重要资料.
A devastating earthquake hit Wenchuan County, Sichuan Province, on May 12, 2008. The earthquake occurred on a section of the fault that was thought to be of moderate seismicity, with few precursors observed before the earthquake. With the coverage of seismic stations, emergency seismology can effectively avoid some of the damage caused by earthquakes and help to the post-earthquake emergency response.From the review point of view, the article proves that only using two three-component seismic stations It is enough to give the location of the error range of 20km to the epicenter of the earthquake within 10s.It is estimated that the magnitude of the earthquake is level 7 from the first 4s signal of the first P wave and the more accurate magnitude estimation can use the Pnl Waveform simulation to complete, at this time just 500km away from the seismic station has received the S wave.Use of 2h after the earthquake occurred more than 5 aftershocks, the rupture area can be well displayed in a few hours, in more detail The rupture process and finite fault model can be obtained by analyzing teleseismic body wave records and can be used to calculate strong ground motions at any time, so as to provide important information for rescue work without real-time strong earthquake records available.