Abstract:

This paper studies the temporal and spatial distribution of global great earthquakes(M_W≥8.0)since 1900.We compare two periods of upsurges of great earthquakes occurring in the middle of last century and beginning of this century. The former took place between 1950 and 1965 when 13 great earthquakes(M_W≥8.0)occurred,including 3 events with moment magnitude greater than 9.0.The maximum magnitude in this period reached 9.6.The later period starts since the beginning of this century. In less than 12 years,15 great earthquakes have attacked the world with the largest magnitude of M_W 9.1.On the basis of comparison of these two upsurges of global earthquake activities,we postulate that the ongoing high level of earthquake activity may continue for another 5 years or so. Numerous great earthquakes(M_W≥8.0)and many large earthquakes(M_W 6～7)will occur globally in this 5 years. In addition,this paper also discusses the relationships between earthquake activities along the Sumatra segment of the Indian-Australia plate boundary and that in the Bayankala block in the middle of the Tibetan plateau as well as the plateau itself. The results indicate that Tibetan plateau,especially its middle and southern parts are the likely places for future earthquakes of magnitude over 7.

Key words: global seismicity, upsurge, seismic risk

摘要：

研究了自1900年以来全球地震活动的时空分布特征,阐明了20世纪中叶和21世纪初2次M_W≥8.0巨大地震的活动高潮,在这2次高潮中多次发生M_W≥9.0巨大地震,对比了这2次全球性地震活动高潮的特征,推测目前正经历的新的地震活动高潮还可能延续5a左右,在此期间,在全球范围内还可能发生多次M_W≥8和6～7级地震。由于青藏高原,尤其是其中部巴颜喀喇断块和南部断块地震活动与印度-澳大利亚板块边界构造带苏门答腊段的地震活动密切相关,要特别注意青藏高原中部和南部发生7级左右地震的危险性。

关键词: 全球性地震活动高潮, 地震危险性, 青藏高原