Zooming into the Hindu Kush slab break-off: A rare glimpse on the   terminal stage of subduction

doi:10.1016/j.eps1.2016.12.043

CORC > 北京大学 > 地球与空间科学学院

	Zooming into the Hindu Kush slab break-off: A rare glimpse on the terminal stage of subduction
	Kufner, Sofia-Katerina ; Schurr, Bernd ; Haberland, Christian ; Zhang, Yong ; Saul, Joachim ; Ischuk, Anatoly ; Oimahmadov, Ilhomjon
刊名	EARTH AND PLANETARY SCIENCE LETTERS
	2017
关键词	Pamir-Hindu Kush slab break-off intermediate-depth seismicity continental crust subduction continental collision repeating earthquakes LOCAL EARTHQUAKE TOMOGRAPHY CRUSTAL ECLOGITIZATION CONTINENTAL-CRUST FOCAL MECHANISMS DEEP EARTHQUAKES MOMENT TENSORS SCOTTS-MILLS SEISMIC DATA PAMIR BENEATH
DOI	10.1016/j.eps1.2016.12.043
英文摘要	The terminal stage of subduction sets in when the continental margin arrives at the trench and the opposite forces of the sinking slab and buoyant continent extend and ultimately sever the subducted lithosphere. This process, although common in geological history, is short-lived, and therefore rarely observed. The deep seismicity under the Hindu Kush (Central Asia), including the 2015 M-w 7.5 event, is a rare case that testifies to this process. Here, we use new seismological data to create a high resolution picture of slab break-off and infer its dynamics. High precision earthquake locations and tomographic images show subduction of continental crust down to 180 km. A large dataset of source mechanisms indicates sub-vertical extension in the entire slab but a strain rate analysis showed that the deeper seismogenic portion of the slab, below the subducted crust, extends at higher rates (similar to 40 km/Ma). Most M-w > 7 earthquakes between 1983-2015, relocated relative to our new well-constrained earthquake catalog, cluster in a small volume below 180 km, and indicate shearing on an overturned interface. A slip model for the latest 2015 M-w 7.5 event suggests that it ruptured into a seismic gap on this interface. From this configuration we conclude that a horizontal slab tear develops along-strike of the Hindu Kush seismic zone at the base of the subducted continental crust. Below the subducted crust, the deepest and also largest earthquakes (180-265 km) are likely associated with deformation in the mantle lithosphere. From the seismicity distribution and the rupture mechanisms we further deduce that the dominant deformation mechanism in this deeper portion of the slab changes along-strike from simple to pure shear. The fastest detachment rates and largest earthquakes occur during the simple shear dominated stage. Earthquakes in the upper part (60-180 km), above the rapidly extending slab, might be triggered by processes related to the subduction of crustal rocks. (C)2017 Elsevier B.V. All rights reserved.; German Federal Ministry of Education and Research [03G0809]; DFG bundle TIPAGE [PAK 443]; SCI(E); ARTICLE; 127-140; 461
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/474924]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Kufner, Sofia-Katerina,Schurr, Bernd,Haberland, Christian,et al. Zooming into the Hindu Kush slab break-off: A rare glimpse on the terminal stage of subduction[J]. EARTH AND PLANETARY SCIENCE LETTERS,2017.
APA	Kufner, Sofia-Katerina.,Schurr, Bernd.,Haberland, Christian.,Zhang, Yong.,Saul, Joachim.,...&Oimahmadov, Ilhomjon.(2017).Zooming into the Hindu Kush slab break-off: A rare glimpse on the terminal stage of subduction.EARTH AND PLANETARY SCIENCE LETTERS.
MLA	Kufner, Sofia-Katerina,et al."Zooming into the Hindu Kush slab break-off: A rare glimpse on the terminal stage of subduction".EARTH AND PLANETARY SCIENCE LETTERS (2017).