2016年广西苍梧MS5.4地震前地震活动图像演化特征  

The Evolution Characteristics of the Seismicity Image Before 2016 MS5.4 Cangwu Earthquake

作　　者：李莎 阎春恒 周斌 郭培兰 周军学 LI Sha;YAN Chunheng;ZHOU Bin;GUO Peilan;ZHOU Junxue(Earthquake Administration of Guangxi Zhuang Autonomous Region,Nanning 530022,China)

机构地区：[1]广西壮族自治区地震局,南宁530022

出　　处：《华北地震科学》2020年第3期19-26,共8页North China Earthquake Sciences

基　　金：广西壮族自治区地震局科研合同制项目(2018001);广西科技计划(桂科AB1850042);广西科技攻关计划项目(桂科攻12426001-1,1377002);中国地震局地震应急青年重点任务(CEAEDEM201910)。

摘　　要：通过分析2016年广西苍梧Ms5.4地震前华南地区地震活动图像及震中附近小震视应力时空变化,得到以下结论:苍梧地震前,震中250 km范围内出现"小震活动增强—小震持续活跃—小震相对平静—发生中强地震"现象;桂西北地区出现3.0级以上地震活跃,季频度达到4次;2012—2016年,华南地区出现中等地震迁移和小震群活跃;震前2年差视应力升高,与震中附近小震活动增强、桂西北地区3级地震活动增强以及华南地区中等地震迁移存在很好的同步性;各类地震活动图像的演化是区域应力增强的伴随现象,苍梧地震在区域应力水平增强背景下发生。This study analyzed the seismicity image of South China before the 2016 Ms5.4 Cangwu earthquake and the temporal and spatial variation of apparent stress of small earthquakes near the epicenter and can obtain the following conclusions.Before the Cangwu Earthquake,there are phenomena which are"small earthquakes increased-small earthquakes continued to be active-small earthquakes were relatively quiet-moderately strong earthquakes"within 250 km of epicenter.In northwest Guangxi,the seismic activity above Ms3.0 become active,and its seasonal frequency reaches 4 times.From 2012 to 2016,moderate earthquake migration and enhanced activity of small earthquake swarms have occurred in South China.The increase of differential apparent stress in two years before the Cangwu earthquake is in good synchrony with the increased seismic activity of small earthquakes near the epicenter,the increased seismic activity of Ms3.0 earthquakes in Northwest Guangxi and the migration of moderate earthquakes in South China.The evolution of various seismicity images is a concomitant phenomenon of regional stress enhancement.The Cangwu earthquake occurred in the background of regional stress level enhancement.

关 键 词：苍梧MS5.4地震 小震活动增强 地震迁移 视应力 

分 类 号：P315.5[天文地球—地震学]