DOI: 10.1016/j.tecto.2020.228321
论文题名: Love-to-Rayleigh scattering across the eastern North American passive margin
作者: Servali A. ; Long M.D. ; Park J. ; Benoit M.H. ; Aragon J.C.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 776 语种: 英语
中文关键词: Eastern North America
; Lithospheric deformation
; Mantle flow
; Seismic anisotropy
; Surface waves
; Wave scattering
英文关键词: Anisotropy
; Offshore oil well production
; Rayleigh scattering
; Seismology
; Surface waves
; Wave energy conversion
; Eastern north america
; Lithospheric deformation
; Mantle flow
; Seismic anisotropy
; Wave scattering
; Coherent scattering
; asthenosphere
; body wave
; deformation mechanism
; lithospheric structure
; Love wave
; mantle process
; passive margin
; Rayleigh wave
; seismic anisotropy
; upper mantle
; wave scattering
; North America
英文摘要: This study presents observations of Love-to-Rayleigh scattering beneath the eastern North American passive margin that place new constraints on seismic anisotropy in the upper mantle. The scattering of Love-wave energy to Rayleigh waves is generated via sharp lateral gradients in anisotropic structure along the source-receiver path. The scattered phases, known as quasi-Love (QL) waves, exhibit amplitude behavior that depends on the strength of the anisotropic contrast as well as the geometrical relationship between the propagation azimuth and the anisotropic symmetry axis. Previous studies of seismic anisotropy in the upper mantle beneath eastern North America have revealed evidence for a mix of lithospheric and asthenospheric contributions, but the interpretation of indicators such as SKS splitting is hampered by a lack of vertical resolution. Complementary constraints on the depth distribution of anisotropy can be provided by surface waves, which have the additional advantage of sampling portions of the margin that lie offshore. Here we present measurements of QL phases using data from several hundred broadband seismic stations in eastern North America, including stations of the USArray Transportable Array, the Central and Eastern U.S. Network, and the MAGIC experiment in the central Appalachians. We find evidence for clear QL arrivals at stations in eastern North America, consistent with a region of particularly strong and coherent scattering inferred just offshore the central portion of the margin. The coherent scattering near the Eastern North American Margin likely reflects lateral transitions in seismic anisotropy in the asthenospheric mantle, associated with locally complex three-dimensional flow, with possible additional contributions from anisotropy in the mantle lithosphere. A second region of strong QL scattering near the southern coast of Greenland is enigmatic in origin, but may be due to pre-existing lithospheric fabric. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170707
Appears in Collections: 气候变化与战略
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作者单位: Department of Geology and Geophysics, Yale University, PO Box 208109, New Haven, CT 06520, United States; National Science Foundation, 2415 Eisenhower Ave., Alexandria, VA 22314, United States; Now at Earthquake Science Center, U.S. Geological Survey, Menlo Park, CA 94025, United States
Recommended Citation:
Servali A.,Long M.D.,Park J.,et al. Love-to-Rayleigh scattering across the eastern North American passive margin[J]. Tectonophysics,2020-01-01,776