DOI: 10.1016/j.epsl.2017.11.031
Scopus记录号: 2-s2.0-85035089401
论文题名: Continental lithospheric subduction and intermediate-depth seismicity: Constraints from S-wave velocity structures in the Pamir and Hindu Kush
作者: Li W. ; Chen Y. ; Yuan X. ; Schurr B. ; Mechie J. ; Oimahmadov I. ; Fu B.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 482 起始页码: 478
结束页码: 489
语种: 英语
英文关键词: crustal subduction
; India–Asia collision
; intermediate-depth seismicity
; Pamir
; stress-field
; surface wave tomography
Scopus关键词: Acoustic wave velocity
; Deformation
; Geodynamics
; Seismic waves
; Seismology
; Shear waves
; Stresses
; Structural geology
; Surface waves
; Tectonics
; Tomography
; Velocity
; Wave propagation
; crustal subduction
; Intermediate depths
; Pamir
; Stress field
; Surface-wave tomography
; Induced Seismicity
; continental collision
; continental lithosphere
; crustal structure
; focal mechanism
; S-wave
; seismic tomography
; seismic zone
; seismicity
; stress field
; subduction
; velocity structure
; Hindu Kush
; Pamirs
英文摘要: The Pamir has experienced more intense deformation and shortening than Tibet, although it has a similar history of terrane accretion. Subduction as a primary way to accommodate lithospheric shortening beneath the Pamir has induced the intermediate-depth seismicity, which is rare in Tibet. Here we construct a 3D S-wave velocity model of the lithosphere beneath the Pamir by surface wave tomography using data of the TIPAGE (Tien Shan–Pamir Geodynamic program) and other seismic networks in the area. We imaged a large-scale low velocity anomaly in the crust at 20–50 km depth in the Pamir overlain by a high velocity anomaly at a depth shallower than 15 km. The high velocity anomalies colocate with exposed gneiss domes, which may imply a similar history of crustal deformation, partial melting and exhumation in the hinterland, as has occurred in the Himalaya/Tibet system. At mantle depths, where the intermediate-depth earthquakes are located, a low velocity zone is clearly observed extending to about 180 km and 150 km depth in the Hindu Kush and eastern Pamir, respectively. Moreover, the geometry of the low-velocity anomaly suggests that lower crustal material has been pulled down into the mantle by the subducting Asian and Indian lithospheric mantle beneath the Pamir and Hindu Kush, respectively. Metamorphic processes in the subducting lower crust may cause the intermediate-depth seismicity down to 150–180 km depth beneath the Pamir and Hindu Kush. We inverted focal mechanisms in the seismic zone for the stress field. Differences in the stress field between the upper and lower parts of the Indian slab imply that subduction and detachment of the Indian lithosphere might cause intense seismicity associated with the thermal shear instability in the deep Hindu Kush. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110132
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; Institutions of Earth Science, Chinese Academy of Sciences, Beijing, 100029, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Deutsches GeoForschungsZentrum-GFZ, Telegrafenberg, Potsdam, 14473, Germany; Institute of Geology, Earthquake Engineering and Seismology, Academy of Sciences of the Republic of Tajikistan, Dushanbe, 734063, Tajikistan; Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing, 100094, China
Recommended Citation:
Li W.,Chen Y.,Yuan X.,et al. Continental lithospheric subduction and intermediate-depth seismicity: Constraints from S-wave velocity structures in the Pamir and Hindu Kush[J]. Earth and Planetary Science Letters,2018-01-01,482