论文部分内容阅读
本文较详尽地研究了唐山7.8级大震后宁河地区6.9级地震前后小地震尾波衰减率 K 在时空上的变化图象。研究结果表明,6.9级地震前某段时间内,唐山地震余震区南端一定深度一定面积范围内,地震尾波衰减 K 增高(即地震尾波衰减快),大震后高 K 值区消失,大部分地震都处在低 K 值状态。此外,本文也探讨了海城和盐源两大地震前后小地震尾波衰减的规律,从某种程度上佐证了大破裂前小地震尾波衰减快,之后衰减慢的事实。而对一些小震群的研究得到震群地震尾波率衰减变化不大的初浅印象。由观测事实出发本文讨论了地震尾波衰减率在大地震前后发生变化的可能原因。
This paper studies in detail the temporal and spatial changes of the wake attenuation rate K of small earthquakes before and after the MS 6.9 Ninghe earthquake in the Tangshan MS7.8 earthquake. The results show that within a certain depth of the southern end of the aftershock area of Tangshan earthquake within a certain period of time before the MS 6.9 earthquake, the attenuation of the tailwave K of the earthquake increases (ie the attenuation of the tail coda is fast) Some earthquakes are in low K state. In addition, this paper also discusses the law of the coda attenuation of small earthquakes before and after the Haicheng and Yanyuan earthquakes, to some extent, it proves the fact that the coda of the small earthquakes before the large rupture decays rapidly and then decay slowly. However, the study of some small swarms obtained the initial impression that the change of the tail wave rate attenuation in the earthquake swarm did not change much. Based on the observations, the possible reasons for the change of the wake coseismic rate before and after the earthquake are discussed in this paper.