基于密集台阵的则木河断裂带地震活动性研究  

Seismicity in Zemuhe fault zone based on dense seismic array

作　　者：姚远[1] 杨周胜[1] 周仕勇[2] Yao Yuan;Yang Zhousheng;Zhou Shiyong(Yunnan Earthquake Agency,Kunming 650224,China;School of Earth and Space Sciences,Peking University,Beijing 100871,China)

机构地区：[1]云南省地震局,中国昆明650224 [2]北京大学地球与空间科学学院,中国北京100871

出　　处：《地震学报》2023年第6期985-995,共11页Acta Seismologica Sinica

基　　金：云南省重点研发计划(社会发展专项)(202203AC100003);云南省地震局“传帮带”项目(CQ2-2021004)共同资助.

摘　　要：利用2019—2021年布设在则木河断裂带的20个宽频带流动测震台和周边6个固定台站的波形数据,对连续波形记录进行P和S震相识别、震相自动关联和初步定位,并应用传统的绝对定位技术得到了研究区绝对地震目录,再运用双差定位法对检测出的1075个地震事件进行重定位。结果表明:①研究区地震活动分布不均匀,多数地震沿着深大断裂带呈条带状分布,显示出断裂在地表的展布形态;②研究区地震的震源优势深度范围为5—15 km,说明本区地震发生在中上地壳;③地震在各个剖面深度的分布特征显示出断裂在深部的构造特征。从重定位后的震中空间分布可见,则木河断裂带中段存在倾向为60°左右的NW向小震密集带,分析认为研究时期以来小震活动频繁,该地区的局部应力较高,构造活动较强。Based on the continuous waveforms of twenty portable broadband seismic stations deployed in the Zemuhe fault and six local stations in the surrounding areas of the fault zone in the period of 2019−2021,we performed automatic earthquake detection with an integrated event detection system called PAL,and then obtained the absolute earthquake catalogue in the study area by using traditional absolute positioning technology,finally relocated 1075 detected seismic events by the double-difference positioning method.The results show that:①The seismic activity in the study area is unevenly distributed,and most of the earthquakes are distributed in strips along the deep-large fault zones,showing the distribution pattern of the fault on the surface;②The focal depth of the earthquakes in the study area ranges 5−15 km,which indicates that the earthquake occurred in the middle to upper crust;③The distribution characteristics of earthquakes at the depth of each section show the structural characteristics of faults in the deep.It can be seen from the spatial distribution of the epicenters after relocation that there is a small earthquake dense zone with dip of 60°in the middle section of the Zemuhe fault zone.The analysis shows that the small earthquakes have been frequent since the study period,the local stress in this area is high,and the tectonic activity is strong.

关 键 词：则木河断裂带 PALM 技术 双差定位 深度分布 

分 类 号：P315.2[天文地球—地震学]