海城-岫岩地震序列发震机理的研究

The M5.7 Xiuyan, Liaoning, China, earthquake of Nov. 29, 1999, occurred at southeastern end of the aftershock zone of the 1975 M7.3 Haicheng earthquake. The sequence of Xiuyan earthquake is characteristically similar to that of Haicheng earthquake: Mainshock focalmechanism of the two earthquake sequences resembles each other; both earthquakes were to some extent impendently predicted and correspondingly the seismic hazards induced by the two earthquakes were mitigated. This earthquake sequence in China is the only one for which large.amount of digital waveform records of foreshocks and aftershocks have ever been registered. This enables us to profoundly study the source rupture process and genesis of the fore-, main- and after-shock sequence. Studying the Haicheng-Xiuyan earthquake sequence helps us in understanding mechanism of the sequence formation and earthquake generation. This is of significance to deepen our insight into the theory of earthquake genesis and prediction..We simulated source rupture process of two mainshocks of the Haicheng and Xiuyan earthquake sequence by using discontinuous deformation analysis and finite element modeling (DDA+FEM). In order to explore fine source structure we introduced the cepstrum analysis of source characteristics on the basis of analysis in frequency domain, and acquired fairly good result for the first stage of the research project. Through the first year exploratory research we have made progress in two aspects: The numerical simulation of Haicheng-Xiuyan earthquake sequence using DDA+FEM approach deepens our understanding of the sequence genesis; the cepstrum analysis is a new approach in source process research and the cepstrum criterion introduced in this study has a good application prospects.

1999年岫岩地震是我国首次记录到大量前、余震数字化波形资料的地震。利用我国及辽宁数字台网的全波记录反演大量前、主、余震的震源过程。研究地震序列发震构造特征，结合海城大震研究结果，用近年发展的块体理论数字模拟海城岫岩地震序列的动力学过程，研究前主余震序列孕育发生的机理。探讨主震发生与小破裂集结演化的过程和规律。