| 强震近震中区地电阻率变化速率的各向异性 |
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| 引用本文： | 杜学彬,阮爱国,范世宏,郝臻.强震近震中区地电阻率变化速率的各向异性[J].地震学报,2001,23(3):289-297. |
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| 作者姓名： | 杜学彬 阮爱国 范世宏 郝臻 |
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| 作者单位： | 1)中国兰州730000中国地震局兰州地震研究所
2)中国北京100081中国地震局地球物理研究所 |
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| 基金项目： | 中国地震局“95-0 4 -0 1 -0 1 -0 9”子专题资助 |
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| 摘 要： | 用归一化月速率方法处理了６次强震前近震中区11个台的地电阻率数据，得到在孕震中短期至短临阶段，与主压应力方向正交（或近于正交）测向的地电阻率下降变化的速率大于平行（或近于平行）主应力方向的变化速率．产生变化速率各向异性的原因可能是:在孕震后期的扩容阶段，裂隙走向沿主压应力方向优势排列，导电流体活动产生真电阻率变化速率的各向异性，表现为地表视电阻率变化速率的各向异性．本文为视电阻率各向异性的实验结果提供了震例支持，物理解释比较清晰，可能成为研究某些强震孕育晚期震源区及其附近地壳应力状态的参考依据．
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| 关 键 词： | 强震近震中区 地电阻率 真电阻率 各向异性 主压应力 |
| 文章编号： | 0253-3782(2001)03-0289-09 |
| 修稿时间： | 2000年5月9日 |
ANISOTROPY OF THE VARIATION RATE OF APPARENT RESISTIVITY NEAR THE EPICENTRAL REGION OF STRONG EARTHQUAKES |
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| Du Xuebin Ruan Aiguo Fan Shihong Hao Zhen Lanzhou Institute of Seismology,China Seismological Bureau,Lanzhou ,China Institute of Geophysics,China Seismological Bureau,Beijing ,China.ANISOTROPY OF THE VARIATION RATE OF APPARENT RESISTIVITY NEAR THE EPICENTRAL REGION OF STRONG EARTHQUAKES[J].Acta Seismologica Sinica,2001,23(3):289-297. |
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| Authors: | Du Xuebin Ruan Aiguo Fan Shihong Hao Zhen Lanzhou Institute of Seismology China Seismological Bureau Lanzhou China Institute of Geophysics China Seismological Bureau Beijing China |
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| Institution: | Du Xuebin 1) Ruan Aiguo 2) Fan Shihong 1) Hao Zhen 1) 1) Lanzhou Institute of Seismology,China Seismological Bureau,Lanzhou 730000,China 2) Institute of Geophysics,China Seismological Bureau,Beijing 100081,China |
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| Abstract: | The apparent resistivity data of 11 stations observed in or near the epicentral regions of 6 strong earthquakes are processed by the normalized monthly rate method. The results show that in the medium short and short imminent terms of earthquake preparation the variation rate perpendicular (or near perpendicular) to the direction of maximum principal compression stress is greater than that parallel (or near parallel) to the direction. Such anisotropic phenomenon is interpreted. The predominated alignment of cracks containing conductive fluid in the maximum principal compression stress direction caused the anisotropy of the fluid migration during the dilatancy process in the late period of earthquake preparation and resulted in the anisotropy of change rate of true resistivity of rock (or solid) medium which induced the anisotropy of the variation rate of apparent resistivity on the ground. The study of this paper provides some practical earthquake examples and a fairly clear physical interpretation for the anisotropic variation of apparent resistivity in pressure experiment, and a reference to determine the stress status near the epicentral regions of certain strong earthquakes during the late period of earthquake preparation. |
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| Keywords: | near epicentral region strong earthquake apparent resistivity true resistivity anisotropy maximum principal compression stress |
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