A Study on Dynamics of Seismic Source or Crack

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In this project, dynamic characteristics of seismic fault or crack were investigated theoretically and experimentally. In theoretical studies, the boundary integral equation method was used, while in experimental studies, the monitoring system of acoustic emissions were employed. This project is mainly divided into two parts. One is concerned with the scattering of elastic waves by seismic fault or crack. The other is the dynamic fracture problems of seismic source or crack.1. Scattering problems of elastic waves: The scattering problems of elastic waves by a crack were theoretically solved by means of the boundary integral equation, which were derived from both the Green's displacement formula and the Green's traction formula. Numerical analyses were carried out for incident body waves and surface waves with a variety of frequency and various geometrical parameters of seismic sources and cracks. The experiments on elastic wave propagation were carried out and compared with the above theoretical results.2. Dynamic fracture problems: As before, theoretical studies on dynamic fracture problems were made by use of the boundary integral equation method. These problems were formulated as moving boundary problems and solved numerically. From fracture experiments of PMMA plates, furthermore, dynamic parameters of AE sources were determined on the basis of the dislocation theory.