2003年云南大姚6.2级、6.1级地震中短期地震学异常演化特征  

Dynamic characteristics of medium and short term seismic anomalies for 2003, M_S=6.2 & M_S=6.1 Dayao earthquakes in Yunnan

作　　者：刘丽芳[1] 付虹[1] 

机构地区：[1]中国科学技术大学地球和空间科学学院

出　　处：《地震地磁观测与研究》2005年第5期33-38,共6页Seismological and Geomagnetic Observation and Research

基　　金："十五"国家科技攻关项目2001BA601B01-02-05课题资助

摘　　要：通过对2003年云南大姚6.2级、6.1级地震中短期地震学特征的分析和初步研究,认为大姚地震孕育过程中的短期阶段,震中附近的地震学异常以中小地震活动增强为主,表现为震区附近中小地震频度增加,4级震群活动、A值、GL值出现异常,同时震源深度加深等;在由中期向短期过渡的过程中,震源区异常消失相对平静,使多种地震学异常收缩至震源区附近;地震孕育进入短临阶段,震中附近地区再次出现了3～4级小震活动增强的特征,云南省地震活动出现向震中附近迁移的趋势。整个孕震过程,地震活动体现了活动-平静-活动的动态演化特征。Characteristics of medium and short-term Dayao earthquakes have been analyzed. It seismic anomalies for 2003, Ms=6.2 ＆ Ms=6.1 indicated that at the medium stage of seismogenic process the seismicity of the moderate and small earthquakes strengthens, and its frequency mainly increases near the hypocentral area, swarm of shocks with M 4-4.9 activates. A value and GL value anomalies appeared and the source depth deepened. At the period between the medium-term and the short-term, then seismicity in the hypocentral area showed relatively quiet, and several anomalies concentrated to the hypocentral area, whereas the really hypocentral area vanished. At the stage of short and imminent term, the earthquakes with M 3-3.9 ＆ M 4-4.9 around the focus area activated again and the seismicity of the whole province had been tendency of immigrating to the focus area. In conclusion, at the whole period of seismogenic process for the Dayao earthquakes, the seismicity indicates dynamic characteristics of activity-quiescence-activity.

关 键 词：大姚地震 地震学异常 动态演化 

分 类 号：P315.73[天文地球—地震学]