时间-震级可预报模式在南北地震带分段危险性评估中的应用

Application of the time-and magnitude predictable model to seismic hazard assessment in segmentation of the north-south seismic belt

为了定量评估南北地震带不同段落的长期地震危险性，引入了时间－震级可预报模式。在详细分析历史地震复发行为的基础上，沿南北地震带划分了３９个震源区。利用其中２７个震源的多轮回复发资料初步建立起时间－震级可预报统计模型。计算结果表明，不同震源的地震复发表现出较好的时间可预报行为以及相对较弱的震级可预报行为。以时间可预报模型为基础，对所有震源区未来地震的复发概率进行了估算，同时，用震级可预报模型对未来地震的震级作了粗略估计。表明在未来３０年内，３９个震源区中有５个发震条件概率Ｐｃ＞０．４，这５个震源区均位于南北地震带南段。

In order to estimate quantitatively long-term seismic hazard in segmentation of the North-South seismic belt, we introduced the time-and magnitude-predictable model into the present study. On the basis of carefully analyzing recurrence behavior of historically strong events, 39 seismogenic sources have been divided along the North-South seis- mic belt. Using data of multiple-cycle recurrence of strong earthquakes on 27 of the 39 sources, we have preliminarily constructed a statistically time and magnitude-predicable model for the belt. The results of calculation suggest that the earthquake recurrence of various seismogenic sources display better time-predictable behavior and relatively poor magnitude-predictable behavior. On the basis of recurrence time probabilistic model rep- resented by the time-predictable equation, we have estimated the recurrence probabilities of the coming earthquakes for the individual seismogenic sources of the belt, and roughly estimated the magnitudes of the future earthquakes from magnitude-predictable equation. The result shows that within the coming 30 years, 5 of the 39 seismogenic sources have conditional probabilities P. higher than 0.4 for earthquake recurrences. These 5 sources are all located in the Yunnan province. Based on the probability values, sources with dif- ferent risk classes have been identified.