江苏地区小震精定位及构造意义分析  

Precise Relocation of Small Earthquakes in the Jiangsu Area and Associated Tectonic Implications

作　　者：霍祝青[1] 瞿旻[1] 

机构地区：[1]江苏省地震局,江苏南京210014

出　　处：《地震工程学报》2016年第5期802-807,共6页China Earthquake Engineering Journal

基　　金：中国地震局三结合资助课题(151005)

摘　　要：利用双差定位法对江苏地区2009-2015年地震记录进行重新定位.结果显示,重新定位后的结果比原有定位精度有了较好的改进,地震序列在空间分布上更加集中;从平面分布上看,重新定位后的地震更加集中于断裂带附近,较多地震呈丛集状出现;从震源深度分布看,研究区内重新定位后地震震源深度有明显收敛,大多集中在5-20km,表明研究区孕震层基本位于地壳的中上部.同时通过对江苏省不同时期发生的几个震群地震构造活动进行分析（分析各个地震序列的走向、是否产生新的断裂带、与原有断裂带走向是否一致等问题）认为其具有十分重要的意义.For this study,we collected one thousand seismic events that occurred in Jiangsu province from 2009 to 2015.Four earthquake sequences occurred successively in this area:Jianhu earthquake sequence,2011;Gaoyou earthquake sequence,2012;Guanyun earthquake sequence,2013;and Donghai earthquake sequence,2015.We relocated these earthquakes using a doubledifference location algorithm.For this analysis it was crucial to establish a reasonable crustal structure therefore,because the double-difference location result was affected by the horizontal velocity model,a more accurate model was required.This paper references the initial model of crustal velocity in Jiangsu and its adjacent regions established by Huangyun.In order to increase the total number of precise location generation events in different areas,this research divided Jiangsu province into seven small areas,and relocated the earthquakes for each.Because the distribution density of the recording stations is different,the number of earthquakes in each area is different.The results show a significant improvement in the relocation results,and the earthquake sequences were found to be more spatially concentrated.The relocated earthquakes were concentrated in obvious bands around faults,and most of them occurred at depths of 5~20km,suggesting the seismological layer in the region lies in the mid-upper crust.By analyzing the seismic tectonic activity of these earthquake swarms,we were able to investigate:the trend of each earthquake sequence,whether or not a new fault zone was initiated,and whether the trends of the new fault zones were consistent with the old ones.This is of great significance to future studies in this area.

关 键 词：双差定位 地震序列 地震构造 

分 类 号：P315.2[天文地球—地震学]