【摘要】 通过对 ( 1 990～ 1 996年 )发生在我国大陆及边境地区 2 4次 6级以上地震的分析研究表明 ,80 %的强震主震前在震源区及附近有中等地震活动增强的过程。异常表现出共同的基本特征 ,即长期平静→增强活动→震前平静→发震。震前平静至发震大约经历几个月到 2年时间 (平均1 0个月左右 ) ,可以作为中短期地震预报判据。用岩石蠕变声发射实验来解释这一现象 ,可把中等地震活动增强看作是稳态蠕变阶段后期发生的广义前震。更多还原

【Abstract】 earthquake with M≥ 6.0 occurred in China’ s mainland from 1 990 to 1 996are analyzed.The research results show thatbefore about80 % ofthe strong earthquakes,the activity of earthquakes became active within and near the epicentral area.The anomaly is expressed in similar process,i.e.,from a long-term quiescence,to moderate earthquake enhancementthen a second quiescence justbefore strong shock,and finally the main shock occurs.The period from the quiescence just before strong shock till the earthquake occurrence is usually aboutseveral months to2 years,with1 0 months on average,which can be used as an index to judge whether the seismogenic process has been into the middleterm to imminent term for earthquake prediction.According to the acoustic emission experiments,the enhancement of the moderate seismicity could be taken as generalized foreshocks occurred atthe end of the stable creep stage.更多还原