全球8级地震序列特征研究

Characteristics of Global Earthquake Sequences with M_W≥8.0

研究地震序列的统计特征，是进行震后地震趋势分析的基础工作之一。通过利用美国国家地震信息中心（NEIC）提供的全球地震目录资料，对1975年以来全球36次8级地震序列进行了研究，重点讨论了震后最大余震强度水平估计问题；并按板内、板缘地震和震源机制类型进行了分类研究。结果表明，不论是在强度（最大余震水平）上，还是在频度（5～6级中强余震频度）上，板内地震与板缘地震存在显著差异：板内地震的最大余震强度和5～6级中强余震活动频度均明显低于板缘地震的；而按震源机制类型分类，这种差异不显著。

Studying the statistic characteristics of earthquake sequences is one of the basic works to analyze postseismic earthquake development trend. By use of NEIC catalogue, We analyze 36 earthquake sequences with Mw ≥ 8.0 in the world since 1975, mainly discuss the estimation of the magnitude of maximal aftershock according to the classification by intraplate earthquake, interplate earthquake and the type of focal mechanism solutions. The resuits show that whether from intensity （the magnitude of maximal aftershock） or frequency （aftershocks with M5 -6 ）, the statistic results are very different between intraplate earthquakes and interplate earthquakes. The magnitude of maximal aftershocks and the frequency of aftershocks with M5 - 6 of intraplate earthquakes are significantly lower than those of interplate earthquakes, but this kind of difference is not obvious when the sequences are classified by the type of focal mechanism solutions.