最大后续地震的强度估计及早期预测应用

THE INTENSITY ESTIMATION OF THE LARGEST SUCCEEDING EARTHQUAKE IN A SEQUENCE AND ITS APPLICATION IN EARLY PREDICTION

使用Ms≥5．0级的80余个地震序列资料，按文献[1]给出的传统分类方法将序列分为主余震型、强震群型（包括双主震型）及孤立型三类，首次分类型统计了第一次大震M1和最大后续地震M2之间的关系，得出线性关系式M2＝a＋bM1及三类序列相应的a、b值．将使用上述关系式计算的M2与序列实际发生的M2比较，若取两者之差｜△M｜≤0．5为标准，内符检验的准确率超过90％．用中小地震序列和历史及现代中、强震资料作外推检验，准确率亦在90％左右．对于大震现场震后趋势判断及最大后续地震的估计具有较高实用价值．为使公式在大震现场工作中便于应用，文中尚给出了以模式识别方法使用M1后一天内资料提取的地震序列综合分类指标，用于早期趋势判断。

Utilizing more than 80 earthquake sequences with magnitude Ms≥5. 0 which are classified into three types: main shock-after shock type, strong earthquake swarm type (including double main earthquake type) and isolated shock type by traditional classification method given by reference [1], the relationship between the first big earthquake M1 and the largest succeding eathquake M2 has been studied,and the linear equation M2=a+bM1 and a, b value have been obtained for different types respectively.The comparison between M2 calcuated from the equation derived in this paper and M2 in the real sequence shows that the accuracy Of the internal coincidence test exceeds 90% under the standard |△M|≤0. 5. It is proved that the accuracy is adout 90% for the extrapolation test using medium-small earthquake sequences and historical or modern medium-strong earthquake data. So this method shows relatively high practiCal value in post-shock trend prediction and the estimation of the largest succeeding earthquake in field study, To appleing this method conveniently to early trend diagnoses in field study, the synthesized classification indexes of the earthquake sequences have been achieved from the sequences data within 24 hours after M1 had drawn form research pattern recognition method.