松原M5.7级地震前视应力特征分析

Characteristic Analysis of Apparent Stress before Songyuan M5.7 Earthquake

摘要: 文章使用吉林省数字地震台网记录的地震波形资料，通过计算得到2017年7月18日至2018年6月12日松原宁江区M_L ≥ 2.5的地震视应力等震源动力学参数。研究视应力变化特征，结果显示，在松原5.7级地震前，滑动平均视应力出现增高趋势，较小震级区间(M_L 2.5~3.0)滑动平均视应力存在显著上升–转折–下降的变化形态，即较大地震前，中小地震视应力存在上升变化，分析认为，松原地区视应力升高异常对该地区地震趋势判定有一定的指示意义。

Abstract: In this paper, the apparent stress and other focal source parameters of ML ≥ 2.5 earthquakes in Ningjiang District, Songyuan from July 18, 2017 to June 12, 2018 were calculated by using the seismic waveform data recorded by Jilin digital seismic network. The characteristics of apparent stress changes are studied. The result shows that before the Songwon M5.7 earthquake, the average apparent stress increases, while in the smaller magnitude range (M_L 2.5~3.0), there is an obvious rising-peak-decline change pattern in slip average apparent stress, that is, before the larger earthquake, the apparent stress of the medium and small earthquakes increases. The analysis shows that the abnormal rise of apparent stress in Songyuan area has certain indicative significance to the judgment of earthquake trend in this area.