地壳校正在长江中下游地区远震层析成像中的应用

利用布设在长江中下游地区的47个固定台站所接收到的473个远震事件，对该地区进行了地壳校正研究。结果显示：(1)内陆地区下方的地壳呈现为低速异常，而沿海地区下方的地壳却呈现为高速异常；(2)地壳校正前后的速度异常确有变化，但差别不是很大，说明长江中下游地区的地壳结构比较稳定；(3)随着深度的增加，速度异常的差别越来越小，说明地壳校正对浅部的速度结构影响较大，而对深部的影响较小。因此，在远震层析成像研究中，若缺少浅部信息，可以进行地壳校正，以消除或减少地壳结构对最终反演结果的影响，从而提高深部结果的质量。

Application of Crust Correction to the Teleseismic Tomography in the Middle and Lower Reaches of Yangtze River Region

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.