中国东北地区地震活动的动力背景及其时空特征分析

Dynamic Background and Space-time Characteristics Analysis of Earthquake Activities in Northeast China

本文根据日本海沟、西太平洋板块俯冲与中国东北地区深源地震的关系、中国东北地区深源地震的平均震源机制结果以及日本海沟强震与中国东北地区浅源地震的关联性,概述了中国东北地区地震活动的动力背景,说明中国东北地区的深源地震与西太平洋板块俯冲具有成因上的联系,中国东北深震是西太平洋板块高速度、小倾角向欧亚大陆下俯冲的结果。中国东北地区深源地震、浅源地震的时空分布以及依据浅源地震的分期统计资料表明,中国东北地区浅源地震经历了5个活动周期,每个活动周期浅源地震的时空分布具有个性差异,在此基础上,分析了浅源地震每个活动周期结束地震时空分布特征,发现每个活动周期结束地震前均经历了平均约4.19年的长时间平静,结束地震以成对地震为主要表现形式。

This paper summarized the dynamic background of seismic activity of northeast China.The results show that there is relationship between deep focus earthquakes and western Pacific subduction plate.These deep shocks are resulted from the western Pacific plate thrusting under the continent of northeast China with small angle（about 26°） and high velocity by means of the relationship between Japan sea trench western Pacific subduction plate and deep focus earthquakes of northeast China,as well as the average results of focal mechanism of deep focus earthquakes of northeast China and the relationship between strong earthquakes of Japan sea trench and deep focus earthquakes of northeast China.The result of space-time distribution of deep focus earthquakes and shallow focus earthquakes as well as activity period of shallow focus earthquakes show that there are five activity periods of shallow focus earthquakes for northeast China,and there is individual difference for shallow focus earthquakes in every activity periods.Based on these,the space-time distribution characteristics of the closing earthquakes of every activity periods for shallow focus shocks are analysed,and find that there is a long calmness of 4.19 years before closing earthquakes characterized by double earthquakes.