DOI: 10.1016/j.epsl.2018.05.010
Scopus记录号: 2-s2.0-85047186918
论文题名: Formation of the frontal thrust zone of accretionary wedges
作者: Weiss J.R. ; Ito G. ; Brooks B.A. ; Olive J.-A. ; Moore G.F. ; Foster J.H.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 495 起始页码: 87
结束页码: 100
语种: 英语
英文关键词: accretionary prism
; fold-and-thrust belt
; numerical modeling
; protothrust zone
; thrust fault formation
; wedge-front deformation
Scopus关键词: Forecasting
; Nucleation
; Numerical models
; Prisms
; Sediments
; Stress analysis
; Viscous flow
; Yield stress
; Accretionary prism
; Elastic stress analysis
; Fold-and-thrust belts
; Forward propagation
; Megathrust earthquakes
; Seismic reflection data
; Thrust faults
; Two-dimensional finite difference models
; Faulting
英文摘要: The combination of recent megathrust earthquakes that have ruptured the frontal portions of accretionary prisms and historical evidence for large wedge-front, fold-and-thrust belt events has sparked interest in the development of wedge-front fault systems. Here we explore the formation of these faults using two-dimensional finite-difference models of spontaneous thrust fault formation and wedge accretion. A reference model with uniform material strength parameters predicts wedge-front thrusts to nucleate near the surface of the sedimentary layer and propagate down towards the basal décollement. The formation of a new frontal thrust is preceded by incipient faulting over a zone several kilometers wide forward of the wedge toe, resembling the protothrust zone (PTZ) imaged in seismic reflection data from the front of submarine accretionary prisms. Similar behavior, with a new frontal thrust forming from top to bottom, occurs if the fraction (λ) of pore-fluid pressure relative to the total (dynamic) pressure is uniform and <0.8 throughout the sediment section, or if λ increases with depth and is <0.7 at the base of the décollement. For greater values of λ models predict more frontal thrusts to form from the bottom to top. These results are reasonably well explained by a simple elastic stress analysis. Models that simulate cohesive brittle strength that is negligible in the shallow sediments and increases with depth also predict new thrust faults to form from top to bottom. Models in which viscous flow at shallow depths represents creep of sediments predict bottom-up thrust nucleation when viscous stresses due to plate convergence remain lower than the brittle yield stress in the top ∼15–50% of the sediment section. Top-down nucleation is otherwise favored when viscous stresses exceed the brittle yield strength throughout most of the sediments. Our study illuminates key controls on the mechanical and temporal links between the PTZ, the forward propagation of slip along the underlying décollement, and the formation of a new frontal thrust. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109823
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: COMET, School of Earth and Environment, University of Leeds, Leeds, United Kingdom; Department of Geology and Geophysics, University of Hawai‘i, Honolulu, HI, United States; U.S. Geological Survey, Earthquake Science Center, Menlo Park, CA, United States; Laboratoire de Géologie, Ecole Normale Supérieure, CNRS UMR 8538, PSL Research University, Paris, France; Hawai‘i Institute of Geophysics and Planetology, University of Hawai‘i, Honolulu, HI, United States
Recommended Citation:
Weiss J.R.,Ito G.,Brooks B.A.,et al. Formation of the frontal thrust zone of accretionary wedges[J]. Earth and Planetary Science Letters,2018-01-01,495