气候变化领域集成服务门户(CCPortal): A recent increase in megathrust locking in the southernmost rupture area of the giant 1960 Chile earthquake

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DOI	10.1016/j.epsl.2020.116200
	A recent increase in megathrust locking in the southernmost rupture area of the giant 1960 Chile earthquake
	Luo H.; Ambrosius B.; Russo R.M.; Mocanu V.; Wang K.; Bevis M.; Fernandes R.
发表日期	2020
ISSN	0012821X
卷号	537
英文摘要	After a great subduction earthquake, viscoelastic stress relaxation causes prolonged seaward motion of inland areas of the upper plate, as was observed around the turn of the century in the area of the 1960 Mw 9.5 Chile earthquake with Global Navigation Satellite System (GNSS) measurements. However, recent GNSS observations during 2010–2019 indicate a systematic decrease in the velocity of the seaward motion over a region covering the latitudinal range of the southern half of the 1960 rupture. Data from the only long-lived continuous site in this region (COYQ since 1997), situated over 200 km away from the trench, suggest that the decrease in the seaward velocity (or increase in the landward velocity) occurred within a few years prior to 2010. This rapid and regional change cannot be explained by viscoelastic relaxation. We thus propose that the change was caused by a relatively sudden downdip widening of the zone of locking along the megathrust. Using three-dimensional finite element modelling, we find that the observed velocity change cannot be otherwise explained, although the amount of the increase in locking cannot be uniquely determined because of trade-offs between, and uncertainties in, the various parameters involved. For example, the degree of the increase in locking is affected by the value of coseismic slip in 1960 in the southernmost part of the rupture zone. A postseismic deformation model with greater coseismic slip in accordance with the most recent coseismic slip model in the literature better fits COYQ data prior to 2005 and requires greater locking increase afterwards. A model with less coseismic slip requires less locking increase but an additional long-term slow slip event prior to 2005. The rapid surface velocity change and the inferred increase in megathrust locking several decades after a great earthquake present new challenges to the understanding of fault mechanics and subduction zone dynamics. © 2020
关键词	enhanced megathrust locking great 1960 Chile earthquake postseismic deformation subduction earthquake viscoelastic stress relaxation
英文关键词	Deformation; Earthquakes; Economic and social effects; Global positioning system; Stress relaxation; Uncertainty analysis; Velocity; Viscoelasticity; Chile earthquakes; Megathrust; Postseismic deformation; Subduction earthquakes; Viscoelastic stress; Locks (fasteners); earthquake event; earthquake rupture; finite element method; GNSS; postseismic process; seismic velocity; stress change; subduction zone; thrust fault; Chile
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202764
作者单位	School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada; Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, Delft, HS 2629, Netherlands; Department of Geological Sciences, University of Florida, Gainesville, FL 32608, United States; Department of Geophysics, University of Bucharest, 6 Traian Vuia Street, Bucharest, RO-020956, Romania; Pacific Geoscience Centre, Geological Survey of Canada, 9860 West Saanich Road, Sidney, British Columbia, Canada; School of Earth Sciences, Ohio State University, 125 South Oval Mall, Columbus, OH 43210, United States; University of Beira Interior, Instituto D. Luiz, Rua Marquês d'Ávila e Bolama, Covilhã, 6201-001, Portugal
推荐引用方式 GB/T 7714	Luo H.,Ambrosius B.,Russo R.M.,et al. A recent increase in megathrust locking in the southernmost rupture area of the giant 1960 Chile earthquake[J],2020,537.
APA	Luo H..,Ambrosius B..,Russo R.M..,Mocanu V..,Wang K..,...&Fernandes R..(2020).A recent increase in megathrust locking in the southernmost rupture area of the giant 1960 Chile earthquake.Earth and Planetary Science Letters,537.
MLA	Luo H.,et al."A recent increase in megathrust locking in the southernmost rupture area of the giant 1960 Chile earthquake".Earth and Planetary Science Letters 537(2020).