摘要
通过对华北地区１９７０～１９９１年震群活动资料的研究发现：①在唐山大震前６～７年，华北地区震群活动出现波浪式起伏增强特点，大震后区域震群活动总体减弱；②唐山大震前的震群逐渐形成条带分布，震后３年条带走向消失；③唐山大震前的震群活动显示出一定的迁移性；④大震前５年，满足ｂ、Ｋ、ｈ、Ｕ和ρ中的任意３个指标的前兆震群在７．８级主震周围大量出现。
Through studying the data of earthquake swarms from 1970 to 1991 in North China, we find: ① Six or seven years before Tangshan earthquake, the enhancement of the earthquake swarm activity showed a fluctuation feature. After the Tangshan earthquake, the regional swarm activity decreased generally; ② Before the Tangshan earthquake with M =7.8, the distribution of the swarms showed in the form of zones, but after the earthquake, the zones disappeared; ③ Before the main shock, earthquake swarms showed a phenomenon of migration; ④ A large number of precursory swarms satisfying the comprehensive indexes only occurred around the mainshock epicenter within 5 years before the earthquake.
出处
《地震》
CSCD
北大核心
1999年第2期183-189,共7页
Earthquake
关键词
震群
前兆震群
唐山地震
时空演化特征
地震前兆
Earthquake swarm, Precursory swarm, Tangshan earthquake, Spatio temporal evolution characteristics
