基于重复地震波形和背景噪声时变特征的川滇主要断层孕震过程研究

川滇地区位于青藏高原东南缘，构造活动剧烈，发育有鲜水河-安宁河-则木河-小江断层系统、大凉山断层、龙门山断层、丽江-小金河断层等诸多断裂系，是中国大陆强震频度最高、灾害最严重的区域之一。应力场控制的地震孕育与发生过程中，断层带及近邻区域速度、各向异性及衰减因子等地震波相关参数会随时间发生变化。利用密集台站记录的重复地震事件波形和背景噪声相关函数时变特征，可以对断裂带区域地下介质物性结构时空变化进行成像，其结果对理解区域强震孕育过程具有重要指示作用。本项目拟基于川滇地区密集台站记录的海量高质量观测波形资料，分析重复地震事件波形和背景噪声相关函数的时变特征，利用理论和观测的波形及包络线拟合方法，反演区域主要断层带及近邻区域地震波相关物性参数时空图像，分析地壳尺度应变场变化与区域强震孕育和迁移关系，探索区域潜在强震风险，为防震减灾与城市建设规划提供重要参考。

Sichuan-Yunnan located in southeastern Tibetan Plateau is a very active tectonic region and there are a lot of fault systems, mainly including Xianshuihe-Anninghe-Zemuhe-Xiaojian fault system, Daliangshan fault, Longmenshan fault and Lijiang-Xiaojinhe fault, etc. It is one of the region in China continent with largest numbers of strong earthquakes and serious hazards. In strong earthquake genesis and rupturing controlled by regional stress field, material properties, including velocity, attenuation and anisotropy, are varied with time. In the project, we will match observed waveforms from repeating events and ambient noises recorded by dense seismic networks/arrays to the theoretical ones, to image the spatial-temporal distributions of material properties related to seismic waves in/around the main faults. With the time-varying material properties structures, the relation between varying crustal strain field and regional strong earthquake genesis and migrations can be obtained, and then we can explore the future of regional strong seismic hazards. The results of the project will be very valuable reference for seismic hazards reduction and city planning.