基于合成地震动的震区烈度划分

Intensity Zoning for Earthquake Area Based on Synthesized Ground Motions

破坏性地震发生后,迅速提供烈度分布情况对救灾工作非常重要。2001年云南永胜地区发生MS6.0地震,布设在永胜期纳台的强震动仪记录到了这次地震。利用随机有限断层法对期纳台的强震动进行了合成,经与实际记录对比认为,合成的地震动较好地反映了真实地震动的主要特征。进一步对震区内169个虚拟观测场点的地震动进行合成,然后利用模糊评定方法由合成地震动计算了震区各虚拟观测场点的仪器烈度,并对震区仪器烈度进行了划分。经与震区烈度实际调查结果对比,认为利用合成地震动划分震区仪器烈度是可行的。

It is very important to supply timely seismic intensity zoning for disaster relier atter a devastating earmquake. In 2001, an earthquake with Ms6.0 occurred in Yongsheng, Yunnan, and the strong ground motion was recorded by a strong motion seismograph at the town of Qina. In this paper, we use stochastic finite fault method to simulate the ground motion at Qina, and compare it with the observational recording, finding that the simulated acceleration time history reflects the main features of actual seismic motion. Furthermore, we layout 169 virtual stations in the earthquake area and synthesize the ground motions of these virtual stations, then evaluate the instrumental seismic intensity of every virtual station based on the seismic motions applying fuzzy method, and obtain the isolines of instrumental intensity for the earthquake area. The comparison of it with real seismic intensity map shows the method is feasible.