摘要
利用区域台网记录的波形资料,基于Brune圆盘断层模型测定了2013年1月—2023年8月期间山西地区500余个2.0≤M_(L)≤4.9地震的震源参数。根据不同震源参数间的定标关系可知,近震震级、破裂半径和应力降与地震矩存在较好的正相关关系,而拐角频率与地震矩呈现负相关关系。通过分区域、分时间段对山西地区2.5≤M_(L)≤3.4地震应力降时空变化特征进行分析研究发现,多次中等地震发生前均出现了应力降持续升高—高值回返—发震与b值下降的协同异常,震中位置多位于高应力降集中分布区域及其附近地区。因此,应力降的大小和强弱可以反映区域介质应力状态的改变,结合b值低值变化时序异常,可为区域震情跟踪与趋势研判提供参考依据。
This study analyzes waveform data from the regional seismic network to determine the source parameters of more than 500 earthquakes(2.0≤ M_(L)≤4.9)in Shanxi Province from 2013 to August 2023,using the Brune circular fault model. Calibration relationships among the source parameters reveal a strong positive correlation between local magnitude,rupture radius,and stress drop with seismic moment,while corner frequency shows a negative correlation with seismic moment. By examining the spatiotemporal variations of stress drop for earthquakes with magnitudes of 2.5≤ M_(L)≤3.4 across different subregions and time periods in Shanxi,we identify consistent anomalies preceding several moderate earthquakes:a sustained rise in stress drop,followed by a decline from elevated values prior to the event,accompanied by a simultaneous decrease in the b -value. Most epicenters were located within or adjacent to areas of concentrated high stress drop. These findings suggest that both the magnitude and intensity of stress drop can serve as indicators of changes in the regional stress state. When integrated with temporal anomalies of low b -values,stress drop measurements provide critical insights for monitoring seismic activity and assessing regional seismic trends.
作者
辛岸佳
李丽
刘剑
王睿敏
王芳
Xin Anjia;Li Li;Liu Jian;Wang Ruimin;Wang Fang(School of Earth Science and Engineering,Hebei University of Engineering,Handan 056038,Hebei,China;Shanxi Earthquake Agency,Taiyuan 030021,China;National Continental Rift Valley Dynamics Observatory of Taiyuan,Taiyuan 030025,China;Institute of Mountain Hazards and Environment,CAS,Chengdu 610299,China)
出处
《中国地震》
北大核心
2025年第3期491-503,共13页
Earthquake Research in China
基金
山西太原大陆裂谷动力学国家野外科学观测研究站项目(NORSTY2023-06)
山西省基础研究计划(202403021211009)
邯郸市科学技术研究与发展计划(23422093034)共同资助。
关键词
震源参数
应力降
时空演化
山西地区
Source parameters
Stress drop
Space-time evolution
Shanxi
