地震弱初始震相及其影响因素的实验研究

项目名称： 地震弱初始震相及其影响因素的实验研究

项目编号： No.41274187

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 刘培洵

作者单位： 中国地震局地质研究所

项目金额： 80万元

中文摘要： 地震成核理论认为，断层失稳从一个准静态过程开始，此时滑动局限在一个小范围内。当滑动位移超出一个临界尺度后，很快变成失稳滑动。因此发现断层的准静态滑动，成为地震预报的关键。低噪声高动态范围的数字地震台的近震源观测结果表明，速度地震图中P波快速突跳前存在一个振幅很小的弱初始震相。因这一震相可与地震成核理论的准静态滑动对应，也被称为地震成核震相。一些研究认为，这种弱的初始震相是广泛存在的，是震源引起，而不是传播路径效应。有一些学者认为弱初始震相的持续时间与最终的地震震级有关，这一点有较大争议。另外弱初始震相的细观力学过程还不清楚。本项目计划通过室内实验研究断层失稳时的弱初始震相。使用粘滑实验模拟断层的失稳过程，用新近购买和研发的高性能声发射系统和变形场监测系统，监测弹性波和变形场，研究弱初始震相和成核区。搞清弱初始震相的力学过程和影响因素。

中文关键词： 地震成核相；弱初始震相；声发射；岩石力学实验；粘滑

英文摘要： The fault instability initiates from a quasi-static generation, which the slip is only limited to a small scale in earthquake nucleation theory. Fault will quickly turn into sliding instability state as the sliding distance is beyond a certain critical scale. Therefore, the identification of quasi-static slip becomes a significant key of earthquake prediction. Nearby observation results from low-noise and high-dynamic range of digital seismic stations show that a typically small amplitude of weakly initial phase occurs before a fast rise of P-wave in seismic speed graphs. Because the earthquake phase may be taken as the quasi-static slip in earthquake nucleation theory, also as earthquake nucleation phase. Some think that the weakly initial phase generally initiated from seismic source, but not in propagation paths. Others suggest that the duration of the weakly initial phase is related to finally seismic magnitude. But, it induces many controversies. Another, the micro-mechanical process is still not clear for weakly initial phase. In this project, the weakly initial phase of fault instability will be investigated by stick-slip experiments of fault in laboratory. And, some newly purchased- and developed- high-performance acoustic emission systems, deformation measurement systems will be used to record elastic w

英文关键词： Seismic nucleation phase；Weak initial phase；Acoustic emission(AE)；Rock mechanics experiment；Stick slip