A STUDY OF LG CODA ATTENUATION BENEATH NORTH CHINA: SEISMIC IMAGING OF LG CODA Q0
华北地区Lg尾波衰减研究——Lg尾波Q0地震成像

By using 560 Lg coda Q 0 values measured on propagating paths, the Q 0 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 Q 0 distribution in the crust beneath the North China region, similar to the velocity image, and closely related with the known surface geological features: the low Q 0 areas exist beneath the Taihang and Yanshan mountains and the Luxi uplift area, and high Q 0 values appear below the Jizhong, Huanghua and Jiyang depressions and the plain areas. There is a clear division between the high and low Q 0 values. Compared with the heat flow values in North China, most the low Q 0 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 Q 0 value areas in the crust of North China, as a whole the North China belongs in low Q 0 value abnormal region. It means that the region is a high seismic wave attenuation area. Probably it is resulted from the interaction between Eurasia and Pacific plates, which causes the crust thinning and hot material upwelling.