DOI: 10.1038/ngeo2013
论文题名: Prolonged canterbury earthquake sequence linked to widespread weakening of strong crust
作者: Reyners M. ; Eberhart-Phillips D. ; Martin S.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2014
卷: 7, 期: 1 起始页码: 34
结束页码: 37
语种: 英语
英文摘要: The Canterbury earthquake sequence in New Zealand was characterized by high-energy earthquakes, a complex pattern of faulting and an extended series of aftershocks. The mainshock occurred in September 2010, yet the largest aftershock occurred 172 days later. Beneath the Canterbury region, the Hikurangi Plateau-a large igneous province that was subducted about 100 Myr ago-remains attached to the crust, welded to greywacke rocks that were fractured during the earthquakes. Here we use three-dimensional seismic tomographic data to investigate the role this crustal structure played in the unusual Canterbury earthquake sequence. We identify a broad, 5-km-wide region centred beneath the surface break and coincident with the depth of maximum fault slip during the mainshock that is characterized by unusually low seismic P-to S-wave velocity ratios of 1.60. Yet before the mainshock this region exhibited ratios of 1.71. We interpret the reduced velocity ratios as the signature of greywacke rocks that have been weakened by the fresh rupture front producing widespread cracking around the fault zone. We suggest that recovery of rock strength between the mainshock and largest aftershock could explain the long delay between the two events. In contrast to a common assumption in aftershock forecasts that crustal strength is constant, we conclude that energetic earthquakes can lead to widespread changes in the strength of Earth's crust. © 2014 Macmillan Publishers Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106432
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: GNS Science, PO Box 30368, Lower Hutt 5040, New Zealand; Department of Geology, University of California Davis, Davis, CA 95616, United States; School of Geography, Environment, and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
Recommended Citation:
Reyners M.,Eberhart-Phillips D.,Martin S.. Prolonged canterbury earthquake sequence linked to widespread weakening of strong crust[J]. Nature Geoscience,2014-01-01,7(1)