A Study of Lg Coda Attenuation beneath North China: Seismic Imaging of Lg Coda Q0

Abstract

AbstractBy using 560 Lg coda Q0 values measured on propagating paths, the Q0 image in the crust beneath the North China region is restructured with a stochastic modeling and the singular value decomposition. The result indicates that there is remarkable lateral heterogeneity on Lg coda Q0 distribution in the crust beneath the North China region, similar to the velocity image, and closely related with the known surface geological features: the high Q0 areas exist beneath the Taihang and Yanshan mountains and the Luxi uplift area, and low Q0 values appear below the Jizhong, Huanghua and Jiyang depressions and the plain areas. There is a clear division between the high and low Q0 values. Compared with the heat flow values in North China, most the low Q0 value areas are located in the high heat flow areas. It is possibly related with hot material activity in the crust below these areas. Although there is a clear difference between the high and low Q0 value areas in the crust of North China, as a whole North China belongs to low Q0 value abnormal regions. It means that the region is a high seismic wave attenuation area. Probably it is resulted from the interaction between the Eurasia and Pacific plates, which causes crust thinning and hot material upwelling.