利用sPn震相精确测定江苏高邮、宝应交界M4.9地震震源深度

Precise Determination of the Focal Depth of Jiangsu Gaoyou-Baoying M4.9 Earthquake by sPn Phase

从江苏省数字地震台网中选取16个宽频带台站的记录资料(震中距范围约为280～380km),利用滑动窗互相关叠加技术提取出sPn震相,并通过sPn与Pn的到时差准确地测定出2012年7月20日江苏高邮、宝应交界M4.9地震的震源深度为9.4km,总的误差小于1.2km。为了验证计算结果,采用与震相走时无关的时域矩张量反演方法(Time-Domain Moment Tensor Inverse),通过反演不同震源深度(5～25km)模型下的矩张量解来进行逆向佐证。结果显示:在震源深度为9、10km时,反演结果的相关系数达到最大,分别约为0.93、0.92,表明9～10km是此次地震的最佳震源深度范围。另外,利用波形互相关的双差定位法得到的震源深度为10.2km,两者相差仅为0.8km。

In this paper, the authors select 16 broadband stations recoroed data from digital mic network in Jiangsu Province, in which the epieentral distance ranges about 280-380 kin. Then using the sliding window cross-correlation overlay technique to extract sPn phase, the focal depth of Gaoyou-Baoying M4.9 earthquake on July 20, 2012 by sPn-Pn, is exactly determined to be 9.4 kin, the total error range less than 1.2 km. In addition, in order to validate the calculation results, we used time-domain moment tensor inverse method, which has not arrival time of phases. By inversion of the different focal depth （5-25 km） models of the moment tensor solution, we find that when focal depth is 9, 10 km, the inversion results of the correlation coefficient rea- ches the maximum, i.e. about 0.93,0.92. This indicates that 9-10 km is the best of focal depth range. Positioning result by the method of double-difference location with waveform cross-correlation is about 10.2 kin. The difference is only 0.8 kin.