ANALYSIS ON THE SEISMIC SOURCE DEPTH DETERMINATION USING SPN PHASE AND ITS APPLICATION
LV Jun -qiang;LI Qing-mei;ZHAO Wei- dong;CAI Xin -hua;CHEN Chun -mei;Earthquake Administration of Ningxia Hui Autonomous Region;
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 depended on the regional crustal model and the focal depth. According to the 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 M4.9 and M4.6 earthquakes occurred at the junction of Yongning, on June. 22, 2010 and October 20, 2012. The results have been compared with those from other sources such as Jopens and China Earthquake Network Center, showing that our results are accurate and reliable.