DOI: 10.1002/2014GL061958
论文题名: Seismic anisotropy and slab dynamics from SKS splitting recorded in Colombia
作者: Porritt R.W. ; Becker T.W. ; Monsalve G.
刊名: Geophysical Research Letters
ISSN: 0094-9460
EISSN: 1944-9191
出版年: 2014
卷: 41, 期: 24 起始页码: 8775
结束页码: 8783
语种: 英语
英文关键词: anisotropy
; Colombia
; SKS splitting
Scopus关键词: Complex networks
; Dynamics
; Seismology
; Tectonics
; Azimuthal anisotropy
; Broadband station
; Colombia
; Perpendicular orientation
; Quaternary volcanisms
; Seismic anisotropy
; SKS splitting
; Wadati-Benioff Zones
; Anisotropy
; Andean orogeny
; Benioff zone
; island arc
; orientation
; polarization
; Quaternary
; seismic anisotropy
; slab
; subduction
; trench
; Caribbean Islands
; Colombia
; Ica
; Nazca
; Peru
英文摘要: The Nazca, Caribbean, and South America plates meet in northwestern South America where the northern end of the Andean volcanic arc and Wadati-Benioff zone seismicity indicate ongoing subduction. However, the termination of Quaternary volcanism at ~5.5°N and eastward offset in seismicity underneath Colombia suggest the presence of complex slab geometry. To help link geometry to dynamics, we analyze SKS splitting for 38 broadband stations of the Colombian national network. Measurements of fast polarization axes in western Colombia close to the trench show dominantly trench-perpendicular orientations. Orientations measured at stations in the back arc, farther to the east, however, abruptly change to roughly trench parallel anisotropy. This may indicate along-arc mantle flow, possibly related to the suggested "Caldas" slab tear, or a lithospheric signature, but smaller-scale variations in anisotropy remain to be explained. Our observations are atypical globally and challenge our understanding of the complexities of subduction zone seismic anisotropy. Key Points Azimuthal anisotropy in much of Colombia shows trench-perpendicular fast axesTrench-parallel fast axes may be due to a lithospheric signal or slab tearResults challenge subduction zone anisotropy and slab dynamics models ©2014. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921731045&doi=10.1002%2f2014GL061958&partnerID=40&md5=2be991d75ea556a24a235e0ae75c4dbb
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/6724
Appears in Collections: 气候减缓与适应
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作者单位: Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
Recommended Citation:
Porritt R.W.,Becker T.W.,Monsalve G.. Seismic anisotropy and slab dynamics from SKS splitting recorded in Colombia[J]. Geophysical Research Letters,2014-01-01,41(24).