太原盆地隐伏断裂潜在最大震级及地震危险性

Seismic Risk and Maximum Magnitudes of Potential Earthquakes for Hidden Faults in Taiyuan Basin

采用双差方法对太原盆地中小地震进行精定位,建立太原盆地隐伏断层统计小区,采用按一定时间尺度归算的震级-频度关系模型,拟合太原盆地隐伏断层的最大地震震级M_(max)与震级频度关系a_(t)/b参数值之间的经验评估模型,综合分析后给出各隐伏活动断层小区的潜在震级上限预测值。采用泊松概率模型,给出各隐伏活动断层发生潜在最大地震震级和中强地震的概率预测结果。结果表明,太原盆地中西部的田庄-文水-汾阳断层统计片区和太原盆地东南部的三佳-洪山-平遥断层统计片区未来发生M_(S)≥6.5地震的概率水平较高;以NW向隐伏活动断层为主的棋子山、北田-王湖断层小区未来发生M_(S)≥6.0地震的概率水平较低。

We use the double difference method to accurately locate small and medium-sized earthquakes in the Taiyuan Basin and establish the sub-area of hidden faults in Taiyuan basin.By using the magnitude frequency relationship model reduced by a certain time scale,we fit the empirical evaluation model between the maximum earthquake magnitude M_(max) of the hidden fault in Taiyuan basin and the magnitude frequency relationship a_(t)/b parameter.After comprehensive analysis,we give the upper limit prediction value of potential magnitude of each active fault zone.To predict the probability of occurrence of potential maximum earthquake magnitudes and moderate-strong earthquake magnitudes for each hidden active fault,we use the Poisson probability model.The results indicate that the Tianzhuang-Wenshui-Fenyang fault area in the central and western parts of the basin,as well as the Sanjia-Hongshan-Pingyao fault area in the southeastern part of the basin,have a higher probability of future earthquakes with M_(S)≥6.5,while the probability level of earthquakes with M_(S)≥6.0 occurring in the future in the Qizishan and Beitian-Wanghu fault areas,mainly composed of NW trending hidden active faults,is relatively low.