| 利用近震高频接收函数研究四川理县西山村滑坡体结构 |
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| 引用本文： | 危自根,储日升,李志伟,盛敏汉,张海江,王宝善.利用近震高频接收函数研究四川理县西山村滑坡体结构[J].地球物理学报,2017,60(10):3793-3803. |
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| 作者姓名： | 危自根 储日升 李志伟 盛敏汉 张海江 王宝善 |
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| 作者单位： | 1. 中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室, 武汉 430077;2. 中国科学技术大学地球和空间科学学院地震与地球内部物理实验室, 合肥 230026;3. 中国地震局地球物理研究所地震观测与地球物理成像重点实验室, 北京 100081 |
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| 基金项目： | 国家重点基础研究发展计划（2013CB733203）和国家自然科学基金（41604056，41661164035）资助. |
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| 摘 要： | 远震接收函数已广泛用于反演台站下方的结构,然而由于地球的非弹性衰减作用,远震数据较难获得高频接收函数,对浅地表结构约束不足.为了克服这一问题,我们使用近震数据的高频接收函数来研究浅表速度结构,并应用于四川理县西山村滑坡体上3个宽频带地震仪记录到的近震事件.本文发展了接收函数V_P-k(V_P/V_S)叠加方法,结合接收函数H-k叠加和波形反演方法获得了台站下方滑坡体的厚度、S波速度和平均V_P/V_S比,并与钻孔得到的滑坡体厚度进行对比.结果表明,滑坡体具有小尺度的横向不均匀性,台站下方滑坡体的平均V_P/V_S比在2.4~3.1之间变化并且在底层存在78~143m·s~(-1)左右的S波低速层.本文观测到的高V_P/V_S比和底层低的S波速度结构,与电磁法获得的滑坡体底层低的电阻率和底部富水特征一致,表明滑坡体h1底界面的抗剪强度相对较弱,是潜在的滑坡危险区域.本文研究结果表明,利用近震接收函数能有效约束浅表的速度结构,进而能为滑坡灾害治理提供一定的地震学参考.
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| 关 键 词： | 理县西山村滑坡体 近震接收函数 VP-k叠加方法 速度横向不均匀性 滑坡灾害治理 |
| 收稿时间： | 2017-05-13 |
Structures of Xishan village landslide in Li County,Sichuan, inferred from high-frequency receiver functions of local earthquakes |
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| WEI Zi-Gen,CHU Ri-Sheng,LI Zhi-Wei,SHENG Min-Han,ZHANG Hai-Jiang,WANG Bao-Shan.Structures of Xishan village landslide in Li County,Sichuan, inferred from high-frequency receiver functions of local earthquakes[J].Chinese Journal of Geophysics,2017,60(10):3793-3803. |
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| Authors: | WEI Zi-Gen CHU Ri-Sheng LI Zhi-Wei SHENG Min-Han ZHANG Hai-Jiang WANG Bao-Shan |
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| Institution: | 1. State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Wuhan 430077, China;2. Laboratory of Seismology and Physics of Earth's Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;3. Seismic Observation and Geophysical Imaging Laboratory, Institute of Geophysics, China Earthquake Administration, Beijing 100081, China |
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| Abstract: | Teleseismic receiver function methods are widely used to study the deep structural information beneath the seismic station. However, teleseismic waveforms are difficult to be used to extract the high-frequency receiver function, hence are insufficient to constrain the shallow structure because of the inelastic attenuation effect of the earth. In this study, using the local earthquake waveforms collected from 3 broadband stations deployed on the Xishan village landslide in Li County in Sichuan Province, we used the high-frequency receiver function method to study the shallow structure beneath the landslide. We developed the VP-k (VP/VS) stacking method of receiver functions, and combined with the H-k stacking and waveform inversion methods of receiver functions to invert for the landslide's thickness, S-wave velocity and average VP/VS ratio beneath these stations, and compared the thickness with the borehole results. Our results show the small-scale lateral variation of velocity structure, a 78~143 m·s-1 lower S-wave velocity in the bottom layer and 2.4~3.1 VP/VS ratio in the landslide. The observed high VP/VS ratio and low S-wave velocity in the bottom layer of the landslide are consistent with low electrical resistivity and rich water in the bottom layer, suggesting a weak shear strength and potential danger zone in landslide h1. Our study suggests that the local earthquake receiver function can obtain the shallow velocity structural information and supply some seismic constraints for the landslide catastrophe mitigation. |
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| Keywords: | Xishan village landslide in Li County local earthquake receiver function VP-k stacking method Velocity lateral heterogeneity Landslide catastrophe mitigation |
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