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DOI	10.1016/j.epsl.2020.116195
	Thick, strong sediment subduction along south-central Chile and its role in great earthquakes
	Olsen K.M.; Bangs N.L.; Tréhu A.M.; Han S.; Arnulf A.; Contreras-Reyes E.
发表日期	2020
ISSN	0012821X
卷号	538
英文摘要	The south-central Chile margin experienced the largest and sixth largest earthquakes ever recorded - the 1960 Mw 9.5 Valdivia and 2010 Mw 8.8 Maule megathrust earthquakes, respectively. In early 2017, we conducted a seismic survey along 1,000 km of south-central Chile to image these rupture zones using a 15.15-km-long multi-channel seismic streamer. We processed these data using pre-stack depth migration, which provides the best look at the shallow part of the south-central Chile margin to date. Relative to other sediment-dominated subduction zones, where sediment is typically accreted at the toe, an unusually large percentage of the thick trench sediments are consistently subducted beneath the slope with little thrust faulting or deformation. Analysis of the sediment P-wave velocities and structure in the trench and outer wedge leads us to conclude that most of south-central Chile contains well-drained, strong sediments. An exception in the vicinity of the subducting Mocha Fracture Zone (MFZ) has trench sediments that appear to experience localized delayed compaction, thus lowering their strength and allowing the development of protothrusts, similar to what is seen in other accretionary subduction zones. The very shallow décollement along the south-central Chile allows more sediment to pass beneath the lower slope than almost all other subduction zone, many of which have much thicker trench sections. We conclude that subduction of the strong, well-drained, thick sediment layer beneath the lower slope is typical for nearly all of the south-central Chile. Comparison to other thick-sedimented subduction zones worldwide reveals that the subduction of such a large fraction of the trench sediment is particularly unusual. This strong, thick, subducting sediment is likely a determining factor for developing a smooth plate interface located well above the subducted crust topography that ultimately becomes a broad megathrust with high, homogeneous frictional properties, and generates particularly large earthquakes along the south central Chile margin. © 2020 Elsevier B.V.
关键词	Chile decollement earthquake sediment subduction trench
英文关键词	Earthquake effects; Earthquakes; Seismic waves; Topography; Trenching; Chile; decollement; Frictional properties; Large earthquakes; Megathrust earthquakes; Multi-channel seismic; Pre-stack depth migrations; subduction; Sediments; crustal thickness; decollement; earthquake event; earthquake magnitude; earthquake rupture; seismic migration; subduction; thrust fault; trench; 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/202819
作者单位	Institute for Geophysics, University of Texas, 10601 Exploration Way, Austin, TX 78758, United States; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 104 CEOAS Admin Building, 101 Southwest 26th Street, Corvallis, OR 97331, United States; Departamento de Geofísica, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, 8370449, Chile
推荐引用方式 GB/T 7714	Olsen K.M.,Bangs N.L.,Tréhu A.M.,et al. Thick, strong sediment subduction along south-central Chile and its role in great earthquakes[J],2020,538.
APA	Olsen K.M.,Bangs N.L.,Tréhu A.M.,Han S.,Arnulf A.,&Contreras-Reyes E..(2020).Thick, strong sediment subduction along south-central Chile and its role in great earthquakes.Earth and Planetary Science Letters,538.
MLA	Olsen K.M.,et al."Thick, strong sediment subduction along south-central Chile and its role in great earthquakes".Earth and Planetary Science Letters 538(2020).