The Simulated Ground Motion of Chengdu Fault in Broadband Frequency by the Hybrid Method
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摘要: 首先,依据成都活断层探测的深、浅层地震勘探资料、钻井资料、地形资料,建立成都地区地下三维介质模型,并基于活断层确定的双石-大川断裂发生7.6级潜在地震的地震活动性探测结果,设定断层破裂震源模型,采用随机有限断层方法模拟短周期地震动、谱元法模拟长周期地震动,利用混合法通过频域合成技术获得了研究区域的宽频地震动。最后,讨论了合成结果的PGA、PGV、PGD以及0.3s和1.0s反应谱的分布特征,依据分布结果对成都市区进行了本次设定地震的地震动讨论。Abstract: Based on the seismic prospecting data of deep and shallow layers, drilling data and topographic data in Chengdu, a deep three-dimensional medium model of Chengdu is established. Then, based on the data of Shuangshi-Dachuan fault survey the rupture source model of MS 7.6 potential earthquake is set up. The stochastic finite fault method is used to simulate the short period ground motion and the spectral element method is used to simulate the long period ground motion. The broadband seismic motion is obtained by the frequency domain synthesis technology of two parts. Finally, the distribution characteristics of the synthetic PGA, PGV, PGD, 0.3s response spectrum and 1.0s response spectrum are given and discussed.
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表 1 双石-大川断裂各段参数
Table 1. The fault parameters of Shuangshi-Dachuan fault
段号 端点纬度/°N 端点经度/°E 走向/° 倾向/° 长度/km 1 31.07 103.62 230 43.85 15 2 30.98 103.53 210 43.74 18 3 30.89 103.47 220 43.59 18 4 30.58 103.16 219 44.49 21 5 30.39 102.98 245 44.49 15 6 30.33 102.85 208 43.27 12 表 2 双石-大川断裂计算参数
Table 2. The computation parameters of Shuangshi-Dachuan fault
参数 设定值 断层长度/km 126 断层宽度/km 24 滑动角/° 90 长度方向分割量(NL) 42 宽度方向分割量(NW) 8 子源的长度/km 3 子源的宽度/km 3 震级 7.6 总面积/km2 3024 最大凹凸体面积/km2 483 次级凹凸体面积/km2 181 破裂速度/km·s-1 2.9 破裂形式 同心圆 震源时间/s 3.01 品子因子Q(f) 500f0.5 应力降/bar 90 -
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