[关键词]
[摘要]
利用基于GPU加速的匹配定位法和双差定位法,对江苏盐城及邻区18个台站记录的2009~2018年共10年的连续地震资料进行分析。首先从台网目录中挑选211个地震事件作为模板事件,使用匹配定位技术对江苏盐城附近连续10年的地震进行检测和识别,共识别出1349个地震事件,约为台网目录地震事件的3倍,最小完备震级由台网目录的ML1.9降为ML1.2。然后利用双差定位法对检测到的地震事件进行精定位,精定位的结果揭示:建湖地区的地震密集带与洪泽-沟墩断裂有关,震源深度优势分布为5~20km,断裂两侧震源深度有显著差异,断裂带倾向NW;射阳震群震源深度比建湖震群有所加深,优势分布为10~25km,震源深度由南东向西北逐渐变浅;宝应地区地震丛集分布;东台地区由于模板事件相对较少,扫描定位后,地震事件在陈家堡-小海断裂带附近零星分布。研究结果为研究盐城地区的地震活动性、发震断层的深部构造提供了基础数据支撑。
[Key word]
[Abstract]
In this paper,the Graphics Processing Unit-based match and locate(GPU-M&L)and double-difference(DD)location algorithm are used to analyze the 10-year continuous seismic data from 2009 to 2018 recorded by 18 stations in Yancheng and its adjacent areas. Firstly,211 seismic events are selected from the network catalog as template events,and then the GPU-M&L is used to detect and identify the earthquakes near Yancheng,Jiangsu Province. A total of 1349 seismic events are identified,which is about 3 times of the network catalog. The nominal magnitude of completeness is reduced from ML1.9 given by the network catalog to ML1.2 given in this study. Then we use the double-difference location algorithm to precisely locate the detected seismic events,and our relocation results show that the seismic intensive zone in Jianhu area is related to Hongze-goudun fault,the dominant distribution of focal depth is 5~20km,the focal depth on both sides of the fault zone has significant difference,the fault zone inclines to northwest;the focal depth of Sheyang earthquake swarm is deeper than Jianhu earthquake swarm,the dominant distribution is 10~25km,and the focal depth gradually becomes shallower from southeast to northwest;Baoying earthquake cluster may be related to Yancheng-Nanyang coast fault. Since there are relatively few template events in Dongtai area,the seismic events are scattered around the Chenjiabao-xiaohai fault zone after scanning and positioning. The results of this paper provide important basic data support for the study of seismicity and deep structure of seismogenic fault in Yancheng area.
[中图分类号]
P315
[基金项目]
国家重点研发计划(2017YFC1500402)、江苏省“十三五”重大项目“盐城市活动断层探测与地震小区划”和上海佘山地球物理国家野外科学观测研究站开发基金(2020K02)共同资助