台湾非火山型震颤发震区结构及其发震机制研究

台湾非火山型震颤（Non-Volcanic Tremors）活动规律特殊，发震位置敏感，揭示其发震区结构、发震机制、发震条件及其与大地震的关系，有助于认识断裂深部活动特征和大地震孕震发震过程，对台湾地震危险性评估和地震前兆现象研究具有重要意义，同时可为大陆强震的孕震提供一定的启示。本申请项目拟以台湾海量地震到时数据和密集台网为基础，分别利用三维各向同性和各向异性地震层析成像技术，开展以下主要工作：（1）开展震颤源区高分辨率三维地震层析成像反演，揭示其精细P波S波速度和泊松比异常结构特征，结合地质背景，揭示其发震机制；（2）开展台湾地区高分辨率三维各向同性和各向异性地震层析成像，获取精细P波S波速度、泊松比异常及P波各向异性结构特征，对比分析不同区域结构、物性、应力场差异，并结合已有地质地球物理资料，揭示震颤发生条件；（3）立足三维成像结果，分析非火山型震颤与大地震之间的构造因果关系。

As one of severely affected areas by earthquakes, non-volcanic tremors are also observed in Taiwan with special characteristics. To study the fundamental properties and physical mechanisms of non-volcanic tremors in Taiwan will provide crucial information into the nucleation processes of nearby huge earthquakes and the complex fault deformation at the bottom of seismogenic layer. Moreover it will be significant to earthquake risk assessments and earthquake precursor studies. In this work, we are going to study the following three contents about non-volcanic tremors in Taiwan by conducting the isotropic and anisotropic seismic tomography based on massive seismic arrival data and the dense seismic network in Taiwan: (i) to determine a 3-D high-resolution P&S-wave velocity anomaly structure and a Poisson’s ratio anomaly structure around the source region, to reveal their physical mechanism and seismic structure; (ii) to determine a 3-D high-resolution P&S-wave velocity anomaly structure, a Poisson’s ratio anomaly structure and the P-wave anisotropy pattern in crust and upper mantle beneath Taiwan, to quantify their generating conditions; (iii) based on our tomography results, to study the structure relationship between non-volcanic tremors and nearby huge earthquakes.