地震活动图像特征与强震危险区经验性预测依据的初步研究

在研究近期（10年）强震危险性判定和总结四川地区1972--2002年强震预测经验的基础上，清理了中国大陆1920--2002年47次浅源大震事件前地震活动图像特征（M≥4．7），提炼出10个方面12项经验性预测依据：主体活动区、多发时段、关联序列、大陆及地区地震异常图像、地区（带）-地段（震源区）地震增强图像（含信号震、诱发地震、地震条带）、相关地震、窗口地震、复发间隔、大陆及地区缺震、地段缺震与地段强震一缺震转折等。它们在47次震例中的综合出现率≥0．58（即依据比7／12以上）占42例；≥0．66（即8／12以上）占34例。因此，强震（M≥4．7）活动图像经验性预测依据可以作为预测有较大可能发生大地震危险区的依据之一。

Seismicity pattern characteristic and empirical indexes for strong earthquakes prediction

According to the studies to judge the risk of a strong earthquake with 10 years scale and the prediction experience of strong earthquakes from 1972 to 2002 in Sichuan province,we summarize the seismicity characteristics before the shallow-focus earthquakes with magnitude equal to or greater than 4.7 occurred in main land of China from 1920 to 2002 and then we put forward 12 empirical prediction indexes from 47 strong earthquakes occurring in main land of China.These indexes include a main seismicity zone,multi-earthquakes period,related seismic series,anomalistic seismicity patterns,increasing seismicity patterns of regions(which include signal earthquakes,induced earthquakes,earthquake zoning),related earthquakes,window earthquakes,recurring intervals,no-earthquakes in some region,no-earthquakes in some belts,and periods between strong and weak seismicities.These comprehensive indexes are tested in the events of 47 earthquakes.These indexes are of valuable in the practice of earthquake prediction.