盐津地震流体前兆异常分析  

Analysis on subsurface fluid precursory anomalies of Yanjin earthquakes

作　　者：张立[1] 申玻 官致君[3] 周挚[4] 

机构地区：[1]中国科学技术大学地球和空间科学学院,安徽合肥230026 [2]昭通市地震局,云南昭通657000 [3]四川省地震局,四川成都610041 [4]云南省地震局,云南昆明650224

出　　处：《地震》2007年第2期121-129,共9页Earthquake

摘　　要：在分析了滇东北地区2006年7月22日、8月25日2次盐津5.1级地震前近震区和外围观测井点地下水物理、化学及断层气CO2异常基础上,总结了地下流体异常特征。研究结果表明:临近地震发生的短期阶段,流体前兆异常数量有增多的趋势;短临阶段在近震区附近出现宏观异常,异常点分布在距震中120 km范围内;从异常点的时空演化特征来看,距震中180km以内的观测井在震前异常显著,异常演化具有扩散、收缩现象;距震中180 km以外的2个二氧化碳观测点均表现为中短期异常,短临阶段有加速转折特征。由此可见,在地震孕育的短临阶段,地下流体微观异常与宏观异常的配套性综合分析是提高预测能力的重要依据。In this paper, the authors analyzed subsurface fluid physical, chemical and CO2＇ s precursory anomalies, including near and outside epicenter region, two Yanjin M5. 1 earthquakes occurred in the Northeast Yunnan region on July 22 and August 25, 2006. At the same time, the authors also summarized the characteristics of subsurface fluid anomalies. The results show that during the short term, the quantity of subsurface fluid precursory anomalies shows rising trend; during the short term and impending stage, macro anomalies near epicenter region are distributed within 120km range. The distribution of anomalies shows a phenomenon of variation and centrality within 180km range, and anomalies appear more. At two sites CO2 shows medium term anomalies, while in short term turning rate become large. Therefore, in the impending stage, the accord integration analysis of micro and macro anomalies is important to improve the forecast ability.

关 键 词：地下流体 地震前兆 异常特征 盐津地震 

分 类 号：P315.7[天文地球—地震学]