全球巨大地震活动性分析

Analysis on global huge earthquake activity

通过分析全球巨大地震活动周期、活跃时段和活动空间分布特征,探讨未来全球发生巨大地震的活跃时段和主体区域.结果表明:①全球地震活动存在着置信度远超过95%的50年左右显著活动周期,此外还存在80—100年左右显著性不强的活动周期;②通过对全球地震MS≥8.3时间序列图和MS≥8.0应变能时间序列图分析,得到活跃期10—14年,平静期39—41年,2004年后又进入了巨大地震的强活跃期,可能会一直持续到2018年;③强活跃时段内发生的MS≥8.5巨大地震存在着一定的相关性,太平洋板块北边界(美国阿拉斯加附近区域—阿留申群岛—千岛群岛)是发生8.5级以上地震最关注的地区,其次是太平洋板块的南美洲边界(尤其是秘鲁及其周边区域),应对这两个地区进行重点关注和监测.本文从地震活动性角度研究巨大地震的强活跃期问题,并推测全球发生8.5级以上地震的活跃时段和主体地区,而对于其机理问题值得进一步深入研究.

This article studied possible active period and regions of future global huge earthquakes by analyzing the characteristics of their recurrence period, activity time and spatial distribution. The result shows： ① Statistically there is a significant cycle of 50 years for global seismic activity, with confidence level far higher than 95%. In addition, there are also 80-100 years activity cycles,which are not so significant as above. ②Through analyzing time series of global Ms≥8.3 earthquakes, we found that globally the active period lasts for 10- 14 years and quiet period is of 39-41 years. The latest strong activity began from 2004, and it may last to 2018. ③ Global huge earthquakes showed evident repeatability. It seems that the northern boundary region of Pacific plate, i. e. , Alaska and its vicinity, Aleutian islands and Kuril islands, is the first area with possible huge earthquake of Ms≥8. 5 in the future, then the South America boundary of Pacific plate, especially Peru and its nearby, would be the second earthquake-prone area. We should focus on and monitor these two areas. The mechanism for huge earthquake recurrence period should be exploited in future.