宁河地区的前震波形特征

CHARACTERISTICS OF FORESHOCK WAVEFORMS IN THE NINGHE REGION

摘要:

唐山7.8级地震后,随即在宁河地区发生一系列地震,称为宁河地震群。
在宁河地震群中发现有七个地震的波形与该区一般地震波形不同,但它们彼此又极为相似。正是这七个波形相似的地震却具有明显的前震性质,在其后差不多时间里,几乎对应了宁河地区全部M_s ≥ 5.5级中强地震。
根据这些波形相似的前震,讨论了宁河地震主破裂面有可能是北西方向左旋节面。

Abstract:

After the Tangshan earthquake(M_s=7.8, July 28, 1976) a series of earthquakes occured in the Ninghe region. It is called the Ninghe earthquake swarm. In the Ninghe earthquake swarm are found seven earthquakes whose waveforms are different from others in the region, but similar to each other. These earthquakes with similar waveforms are characterized significantly by the foreshock. Such earthquakes are regularly followed by moderate-strong earthquakes with magnitude Ms ≥ 5.5 about the same period in the Ninghe region. Based on the such foreshocks with similar the main waveforms, the main fracture plane in the Ninghe region has been investigated, and it may be the left-lateral nodal plane orientated NW.