The 11 April 2012 east Indian Ocean earthquake triggered large aftershocks worldwide
The 11 April 2012 east Indian Ocean earthquake triggered large aftershocks worldwide
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DOI：
10.1038/nature11504
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发表时间：
2012-10-11
期刊：
影响因子：
64.8
通讯作者：
Buergmann, Roland
中科院分区：
文献类型：
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作者：
Pollitz, Fred F.;Stein, Ross S.;Buergmann, Roland
大地震在地震波传播期间以及随后的几个小时到几天(1-10日)在全球范围内触发了非常小的地震，但到目前为止还没有发现M>；=5.5级的遥远余震(11)，唯一的例外是由4,800公里外6.6级地震的面波远程触发的M=6.9地震(12)。2012年东印度洋发生的地震，震级为8.6级，是有记录以来最大的走滑事件。结果表明，在2012年地震后的6天内，全球5.5级地震(距震中1,500公里)的出现率增加了近5倍，并且在过去十年中扩展到8.5级主震是冲断的；在这些事件之后，全球5.5级地震的出现率比2012年地震后增加了约三分之一，而且只持续了两天，这是一个较弱但可能是实际增长的数字。我们认为，2012年地震史无前例的延迟触发能力可能是因为它的走滑震源几何结构，或者是因为这次地震发生在全球地震率异常低的时候，可能增加了非常接近破裂的成核地点的数量。
Large earthquakes trigger very small earthquakes globally during passage of the seismic waves and during the following several hours to days(1-10), but so far remote aftershocks of moment magnitude M >= 5.5 have not been identified(11), with the lone exception of an M = 6.9 quake remotely triggered by the surface waves from an M = 6.6 quake 4,800 kilometres away(12). The 2012 east Indian Ocean earthquake that had a moment magnitude of 8.6 is the largest strike-slip event ever recorded. Here we show that the rate of occurrence of remote M >= 5.5 earthquakes (>1,500 kilometres from the epicentre) increased nearly fivefold for six days after the 2012 event, and extended in magnitude to M = 8.5 main-shocks during the past decade are thrusts; after these events, the global rate of occurrence of remote M >= 5.5 events increased by about one-third the rate following the 2012 shock and lasted for only two days, a weaker but possibly real increase. We suggest that the unprecedented delayed triggering power of the 2012 earthquake may have arisen because of its strike-slip source geometry or because the event struck at a time of an unusually low global earthquake rate, perhaps increasing the number of nucleation sites that were very close to failure.