本文推导了sPn与Pn波走时差与震源深度的关系. 方程中sPn与Pn波的走时差与震中距无关,只与区域地壳模型和震源深度有关. 根据该方程,提出用近震震相sPn与Pn的走时差来测定地震深度的简便、准确方法. 运用本方法对2008年8月30日和8月31日发生在四川省攀枝花和会理交界处的MS6.1、 MS5.6两次地震的震源深度进行了测定,并与中国地震台网中心的结果进行了对比,所测得的结果准确、可靠.%In this paper, we derived the relationship between the travel time difference of sPn and Pn and the local earthquake focal depth. In these equations, the travel time difference of sPn and Pn is not related to the epicentral distance, only only depended on the regional crustal model and the focal depth. According to equation, we provided a simple and accurate method to determine local earthquake focal depth by using the travel time difference between phase sPn and Pn. This method has been used to determine the focal depths of two earthquakes of Ms6.1 and Ms5. 6 occurred at the junction of Panzhihua and Huili,Sichuan on Aug. 30 and 31, 2008. The results have been compared with those from other sources such as China Earthquake Network Center, showing that our results are accurate and reliable.
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