2018年5月28日吉林松原M_S5.7地震发震构造分析

Seismogenic structure analysis of the M_S5.7 Songyuan,Jilin,earthquake on May 28,2018

利用黑龙江、吉林、内蒙古三省数字地震台网的三分量宽频带波形资料对2018年5月28日吉林省松原市宁江区发生的M_S5.7地震进行了全波形矩张量反演,获取了此次地震的震源机制解和矩心位置;并使用震源-矩心方法讨论了该地震的发震断层。研究结果显示:松原M_S5.7地震的矩震级为MW5.2,矩心位置为(45.225°N,124.685°E),矩心深度为7 km。震源机制解参数显示:该地震为走滑型;节面Ⅰ的走向、倾角和滑动角分别为217°,82°和164°;节面Ⅱ的走向、倾角和滑动角分别为309°,74°和8°;双力偶成分占96.4%,方差减少为93%。震源-矩心图显示震源更接近节面Ⅰ,与北东向的扶余—肇东断裂走向及倾角一致,因此,推测扶余—肇东断裂为发震断层。

Based on the three-component waveform data of regional broadband stations of Heilongjiang,Jilin and Inner Mongolia digital seismic networks,the full waveform moment tensor inversion for the M_S5.7 earthquake occurred in Ningjiang district of Songyuan,Jilin Province,on May 28,2018 is carried out,and the focal mechanism solution and centroid position of the earthquake are obtained. And then the hypocenter-centroid method is used to determine the actual seismogenic fault. The results show that the moment magnitude is MW5.2,centroid position is(45.225°N,124.685°E),and centroid depth is 7 km. The mechanism parameters of the earthquake are: strike 217°,dip 82°,rake 164° for the nodal planeⅠ,strike 309°,dip 74°,rake 8° for the nodal planeⅡ,and the event is of strike-slip type. Moreover,double-couple component is 96.4%,and variance reduction is 93%. The hypocenter-centroid plot indicates that the hypocenter is close to nodal plane Ⅰ,which is consistent with the strike and dip angle of the Fuyu-Zhaodong fault. Therefore,it is indicated that the Fuyu-Zhaodong fault is the real fault plane.