Abstract:

This paper applied a crust correction method to study the middle and lower reaches of Yangtze River region, and the data used in the study were derived from 473 teleseismic events collected by 47 permanent stations. The results show that (1)the low crust velocity anomaly is beneath inland area and the high crust velocity anomaly is beneath coastal area; (2)there are slight velocity-anomaly differences between before and after crust correction, indicating that the crust structure of the middle and lower reaches of Yangtze River region is stable; (3)with the depth increasing, the difference of velocity anomaly is becoming smaller, which means the impact of crust correction method in shallow depth is big while in deep depth is small. Therefore, in the teleseismic tomography study, if shallow information is shortage, the crust correction can be used to eliminate or reduce the influence of crust velocity structure to the final inverse results, and improve the quality of results in deep depth.

Key words: the middle and lower reaches of Yangtze River region, crust correction, teleseismic tomography, 3-D crust model