摘要
基于山西数字地震台网2001—2010年记录的地震,研究临汾地区的地震活动,并寻找重复微震,进而计算深部滑动速率。双差法重新定位后的地震图像显示,在研究时段内,临汾地区29.3%以上的地震发生在临汾盆地平原腹地的苏堡断裂两侧,即沿NNE向分布南、中、北3个隆起间的2个次级凹陷之一的临汾-洪洞次级凹陷内;震源深度分布与研究区的深部构造较为相符。通过波形互相关分析,识别出波形高度相似的49组相似地震对和25组多重相似对。大部分相似地震活动表现为非周期性,复发间隔从数分钟到数百天不等。依据在同一地震台站记录的波形塑造参考地震的波形,用以量取每个地震相对于参考地震的S—P相对到时差,并确定每个地震与多重相似对质心的相对距离,从而挑选出每组地震中的重复事件。识别出研究区2组重复地震,并由此估算得到滑动速率为1.9~2.8mm/a,该值与同时段GPS和地质等浅表观测的滑动速率值基本相符。
Based on the earthquakes recorded from Shanxi digital seismic network in 2001—2010,we study the seismic activity in Linfen region in order to look for repetitive microtremors,and then calculate the rate of deep sliding along faults.,The earthquake image after relocating by using double-difference method shows that more than 29.3%earthquakes during the study period occur on both sides of Subu fracture in the hinterland of Linfen Basin plain,namely the Linfen-Hongtong secondary depression,which distributed between south,middle and north three uplifts along NNE.Focal depth distribution and deep structure in the study area is relatively consistent.Through waveform cross-correlation analysis,we identify 25 groups of similar pair of earthquakes and 49 groups of multiple similar pair with high waveform similarity.Most similar seismic activities are characterized by aperiodic,with recurrence intervals ranging from several minutes to several hundred days.Based on the records in the same seismic station,we firstly create reference seismic waveform,which is used to measure the S—P relative arrival time difference of each earthquake relative to the reference one,and then determine the relative distance of each earthquake to the center of mass of multiple similar pair,so that to pick out the recurring events in each group of earthquakes.Finally we identify 2 groups of repeated earthquakes in the study area,and estimate the sliding rate of 1.9~2.8mm/a,which is basically similar to that from surface observations such as GPS and geological survey at the same period.
作者
董春丽
李乐
李冬梅
王卓君
梁永烨
Dong Chunli;Li Le;Li Dongmei;Wang Zhuojun;Liang Yongye(Shanxi Taiyuan Continetal Rift Dynamics National Observation and Research Station,Taiyuan 030025,China;Shanxi Earthquake Agency,Taiyuan 030021,China;Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China)
出处
《中国地震》
北大核心
2021年第4期878-887,共10页
Earthquake Research in China
基金
中国地震局星火项目(XH1004Y)资助。
关键词
临汾地区
重复微震
滑动速率
Linfen area
Repeating microearthquake
Slip rate of fault
