DOI: 10.1016/j.tecto.2021.228948
论文题名: Observation-constrained multicycle dynamic models of the Pingding Shan earthquake gate along the Altyn Tagh Fault
作者: Liu D. ; Duan B. ; Prush V.B. ; Oskin M.E. ; Liu-Zeng J.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2021
卷: 814 语种: 英语
中文关键词: Altyn Tagh fault
; Dynamic rupture
; Earthquake cycle
; Earthquake gate
; Fault geometric complexity
; Stress heterogeneity
英文关键词: Copper mines
; Faulting
; Geometry
; Stiction
; 2-D finite element method
; Dynamic ruptures
; Earthquake cycles
; Earthquake recurrence intervals
; Earthquake rupture
; Geometric complexity
; Recurrence intervals
; Stress evolution
; Earthquakes
; earthquake event
; earthquake rupture
; fault geometry
; finite element method
; model
; recurrence interval
; stress field
; Altyn Tagh Fault Zone
; China
英文摘要: Earthquake gates are fault geometric complexities, common in natural fault systems, that conditionally impede earthquake ruptures. This study centers on modeling of multicycle dynamics of the Pingding Shan earthquake gate along the central Altyn Tagh Fault in northwest China. The earthquake gate includes three geometric complexities: a prominent restraining bend, a 4-km wide stepover to the east, and a releasing bend to the west. We use a 2D finite element method to simulate coseismic spontaneous ruptures with interseismic fault stress evolutions computed by an analytic viscoelastic solution. Paleoseismic records and long-term slip-rates are used to constrain the models. We find that fault-geometry-related heterogenous stresses accumulated over earthquake cycles yield complex rupture patterns and help explain earthquake recurrence intervals revealed by paleoseismic records. The three most important contributions to the heterogeneous stresses come from dynamic ruptures passing fault geometric complexities, fault-strike-dependent tectonic loading and relaxation, and stress history from past earthquakes. In the Pingding Shan earthquake gate, the releasing stepover appears to impede ruptures more effectively than the restraining bend. The combined impact of the restraining bend and the releasing stepover makes the Pingding Shan earthquake gate a very effective barrier to 350-km model-spanning ruptures. The best-fit model yields a low recurrence interval of 4.6 kyrs for 350-km-long ruptures, interspersed with more frequent ruptures limited to individual fault segments. A lower static friction tends to reduce the effectiveness of the earthquake gate to impede ruptures. Local fault geometric complexities together with rapid energy release and restrengthening of friction during dynamic ruptures help explain the 0.66 recurrence interval coefficient of variation (COV) recorded at the Copper Mine paleoseismic trench site on the Xorxoli segment. This study provides a method for applying heterogenous initial stresses for single-event dynamic rupture simulations that consider the effect of past earthquakes and fault geometry. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170847
Appears in Collections: 气候变化与战略
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作者单位: Center for Tectonophysics, Department of Geology & Geophysics, Texas A&M University, College Station, TX 77843-3115, United States; Department of Earth and Planetary Sciences, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, United States; Institute of Surface-Earth System Science, Tianjin University, Tianjin, 300072, China
Recommended Citation:
Liu D.,Duan B.,Prush V.B.,et al. Observation-constrained multicycle dynamic models of the Pingding Shan earthquake gate along the Altyn Tagh Fault[J]. Tectonophysics,2021-01-01,814