晋冀鲁豫交界地区中小地震视应力特征研究

利用邯郸测震台网记录的2005—2016年晋冀鲁豫交界地区的地震波形资料, 采用近震Brune模型, 结合遗传算法反演计算了302次2.0≤M_L<4.3中小地震的视应力值, 得到晋冀鲁豫交界地区视应力取值范围为0.01~3.26 MPa, 平均为0.535 MPa, 讨论了震源参数之间的标度关系, 分区分析了晋冀鲁豫交界地区的时序变化特征和中强地震前视应力时空变化特征, 结果表明: 晋冀鲁豫交界地区多地出现显著的视应力高值异常, 地震多发生于视应力高值异常区域及其附近地区, 通过分析具体震例发现绝大多数地震发生前均出现视应力高值异常,视应力高值异常对中强地震空间位置预测有一定的指示作用, 可以作为晋冀鲁豫交界地区地震危险性判断依据。

Characteristics of Apparent Stresses of Small and Moderate Earthquakes in the Border Area of Shanxi,Hebei, Shandong and Henan Provinces

Based on the seismic waveform data from 2005 to 2016 in the border area of Shanxi-Hebei-Shandong-Henan provinces recorded by Handan Seismic Network, apparent stress values of 302 small and moderate earthquakes (2.0≤M_L<4.3) were calculated using near-surface Brune model and genetic algorithm. The range of apparent stresses of Shanxi-Hebei-Shandong-Henan border area is 0.01—3.26 MPa, with an average of 0.535 MPa. The scaling relationship between source parameters is discussed. The spatial and temporal characteristics of stresses are analyzed. The results show that there are some obvious high values of apparent stress and stress anomalies in many areas at the border area of Shanxi, Hebei, Shandong and Henan Provinces. The earthquakes mostly occur in the area of high apparent stress anomaly and its vicinity, and high apparent stress anomalies occurred before the majority of earthquakes. The results indicate that the abnormal high apparent stress give some indication to the prediction of the epicenters of moderate to strong earthquakes, which can be used as the basis of earthquake risk judgment at the border area of Shanxi, Hebei, Shandong and Henan.