2017年9月4日河北临城M_L4.4地震震源深度测定

震源深度是地震定位中的重要参数之一。对于一个地震,sPn与Pn震相到时差是一个常量,与震中距无关,只与震源深度和地壳模型有关。基于该理论,以河北数字台网数据为基础,识别sPn震相和Pn震相,计算2017年9月4日河北临城ML4.4地震震源深度,结果为6.86km。双差定位法是目前确定震源深度比较精确的方法,双差定位得到的震源深度为7.01km。双差定位法所用数据量比较大,计算过程繁杂。利用sPn与Pn到时差计算震源深度的结果与双差定位法结果接近,计算快速、简单,所需数据量小。因此,将该方法应用到实际工作中,可以快速、准确地测定近震震源深度。

Determination of Focal Depth for the Lincheng M_L4.4 Earthquake in Hebei on September 4,2017

Focal depth is one of the important parameters in seismic location.For an earthquake,the arrival time difference between sPn and Pn is a constant,independent of epicenter distance,and only related to focal depth and crustal model.Based on this method and the data recorded by the Hebei digital seismic network,the sPn and Pn phases are identified,and the focal depth of the ML4.4 Lincheng earthquake on September 4,2017 is calculated,with the result is 6.86 km.The double-difference location method is a more accurate method to determine the focal depth at present,and the focal depth obtained by the double-difference location is 7.01 km.However,the data used in this double-difference location method is rather large and the calculation process is complicated.Considering that the focal depth by using sPn-Pn arrival time difference is close to that of double-difference location,the calculation is fast and simple,and the amount of data needed is small,we think that this method can be applied to practical work to determine the focal depth of near earthquakes quickly and accurately.