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ISSN 2096-7780 CN 10-1665/P

巴振宁, 赵靖轩, 吴孟桃, 梁建文, 塔拉. 逆断层地震作用下三维沉积盆地地震动谱元法模拟[J]. 地震科学进展 , 2020, (10): 13-22. DOI: 10.3969/j.issn.2096-7780.2020.10.002
引用本文: 巴振宁, 赵靖轩, 吴孟桃, 梁建文, 塔拉. 逆断层地震作用下三维沉积盆地地震动谱元法模拟[J]. 地震科学进展 , 2020, (10): 13-22. DOI: 10.3969/j.issn.2096-7780.2020.10.002
Zhenning Ba, Jingxuan Zhao, Mengtao Wu, Jianwen Liang, La Ta. Spectral element method simulation of three-dimensional sedimentary basin under reverse-fault earthquakes[J]. Progress in Earthquake Sciences, 2020, (10): 13-22. DOI: 10.3969/j.issn.2096-7780.2020.10.002
Citation: Zhenning Ba, Jingxuan Zhao, Mengtao Wu, Jianwen Liang, La Ta. Spectral element method simulation of three-dimensional sedimentary basin under reverse-fault earthquakes[J]. Progress in Earthquake Sciences, 2020, (10): 13-22. DOI: 10.3969/j.issn.2096-7780.2020.10.002

逆断层地震作用下三维沉积盆地地震动谱元法模拟

Spectral element method simulation of three-dimensional sedimentary basin under reverse-fault earthquakes

  • 摘要: 近断层地震动对近场区域会造成严重的地震灾害,尤其区域内存在沉积地形时会进一步加重灾害。目前,针对释放能量更大、破坏力更强的逆冲断层地震作用下沉积盆地的地震动响应研究还未见报道。本文即采用谱元法,研究了动力学逆断层地震作用下的三维沉积盆地的动力响应。文中以椭球形沉积盆地为例,对其逆断层地震动响应特性进行了分析,并探讨了改变内外介质波速比和沉积厚度时沉积盆地内部观测点地震动时程和峰值变化规律。研究表明:①沉积内外介质波速比对沉积盆地的地震动影响显著,当沉积内部介质波速比降低时,盆地内部地表的峰值响应增大,地震动持续时间明显延长,尤其是位于盆地中心加速度峰值放大2.08倍,持时延长1.97倍;②沉积盆地厚度同样对其地震动响应产生影响,当沉积厚度增加时盆地中心位置地震动响应减小,加速度峰值缩小约0.64倍,而盆地边缘区域的地震动响应明显增大,峰值放大约1.35倍。

     

    Abstract: Near-fault ground motion can cause serious earthquake disaster in the near-field area, especially when there is sedimentary topography in the area. At present, there are no reports on the ground motion response of sedimentary basins under the action of thrust faults which release more energy and have more destructive force. In this paper, spectral element method is used to establish the overall physical model of the dynamic source containing the reverse fault and the three-dimensional sedimentary basin. The dynamic response of the three-dimensional sedimentary basin under the dynamic reverse fault seismic action is studied. Taking an ellipsoid sedimentary basin as an example, this paper analyzes the characteristics of the ground motion response of its reverse faults, and discusses the time-history and peak variation of the ground motion at the observation points in the sedimentary basin under different wave velocity ratios and thickness of the sedimentary medium. The results show that: ① The wave velocity ratio of medium inside and outside the sedimentary basin has a significant influence on ground motion in the sedimentary basin. When the wave velocity ratio of medium inside the sedimentary basin decreases, the peak response on the surface inside the basin increases, and the duration of ground motion significantly extends. In particular, the peak acceleration in the center of the basin magnifies by 2.08 times, and the duration extends by 1.97 times; ② The thickness of a sedimentary basin also has an impact on its ground motion response. When the sedimentary thickness increases, the ground motion response at the center of the basin decreases by 0.64 times, while the ground motion response at the edge of the basin increases significantly, by about 1.35 times.

     

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