断层带围陷波理论分析与研究

Research on fault zone structures has important significance for understanding earthquake preparation and occurrence, the course of rupture and earthquake disasters, and so it is always a focal point of research. Because fault zone trapped waves propagate along the inner of fault zones, they embody important information of fault zones, and their amplitudes and frequencies are strongly dependent on the fault geometry and physical properties. So fault zone trapped waves are the powerful tool for studying the fine structures of fault zones. Since the research on trapped waves is insufficient, the application and development of this method are limited. Now，the effect of hypocenters and velocity interface in fault zones on trapped waves, and the travel distance and depth characteristics of trapped waves are not clear, so this project will study them. At the same time, this project will try to carrying out the study for quantitative analysis of relations between fault zone structures and waveform characteristics of trapped waves, and for quantitative inversion method for trapped waves. Theory researches on trapped waves will provide support to applications for fault-zone structures.

断层带结构研究对于认识地震的孕育发生、地震破裂过程及其地震灾害具有重要的意义，所以一直是地震学研究的热点之一。由于断层带围陷波沿断层带的内部传播，振幅和频率特性与断层带的几何参数和物理性质密切相关，因而成为研究断层精细结构的有力工具。由于对围陷波的相关理论研究不足，限制了其应用和发展。目前，关于震源和断层带内速度界面对围陷波影响以及围陷波传播深度和距离特点等还不清楚，本项目将通过数值模拟方法对这些问题进行重点研究。同时，尝试开展断层带结构参数与围陷波的波形特征之间的定量关系和围陷波定量反演分析方法方面的研究，为断层带围陷波在探测断层带结构方面的应用提供进一步的理论支持。

本项目模拟了大量不同断层带结构参数下三维断层带的围限波理论波场，对围限波的频谱进行深入的对比分析，研究了断层带宽度、断层带内外P、S波速度、浅部速度界面、震源等断层带结构参数对围限波频谱、振幅和波形的影响，提出了利用围限波频谱分析和频散曲线测量、波形互相关测量、围限波波形模拟与基于结构参数的网格搜索方法和多种方法相结合的确定断层带结构参数定量分析方法。相关研究成果对认识围限波的传播与波形特征以及与断层带结构参数之间的关系具有重要的理论意义，同时在断层带围限波的观测方案设计及利用围限波特征确定断层带结构参数方面具有重要的应用意义。