DOI: 10.1038/ngeo1991
论文题名: Viscous roots of active seismogenic faults revealed by geologic slip rate variations
作者: Cowie P.A. ; Scholz C.H. ; Roberts G.P. ; Faure Walker J.P. ; Steer P.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2013
卷: 6, 期: 12 起始页码: 1036
结束页码: 1040
语种: 英语
Scopus关键词: active fault
; fault zone
; power law
; seismology
; shear zone
; slip rate
; strain
; strain rate
; topographic mapping
; viscous flow
; Apennines
; Italy
英文摘要: Viscous flow in the deep crust and uppermost mantle can contribute to the accumulation of strain along seismogenic faults in the shallower crust. It is difficult to evaluate this contribution to fault loading because it is unclear whether the viscous deformation occurs in localized shear zones or is more broadly distributed. Furthermore, the rate of strain accumulation by viscous flow has a power law dependence on the stress applied, yet there are few direct estimates of what the power law exponent is, over the long term, for active faults. Here we measure topography and the offset along fault surfaces created during successive episodes of slip on seismically active extensional faults in the Italian Apennines during the Holocene epoch. We show that these data can be used to derive a relationship between the stress driving deformation and the fault strain rate, averaged over about 15 thousand years (kyr). We find that this relationship follows a well-defined power law with an exponent in the range of 3.0-3.3 (1σ). This exponent is consistent with nonlinear viscous deformation in the deep crust and, crucially, strain localization promoted by seismogenic faulting at shallower depths. Although we cannot rule out some distributed deformation, we suggest that fault strain and thus earthquake recurrence in the Apennines is largely controlled by viscous flow in deep, localized shear zones, over many earthquake cycles. © 2013 Macmillan Publishers Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106646
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Department of Earth Science, University of Bergen, Bergen 5002, Norway; Lamont Doherty Earth Observatory of Columbia University, Palisades, NY 10964-8000, United States; Department of Earth and Planetary Sciences, Birkbeck College, University of London, London WC1E 7HX, United Kingdom; Institute for Risk and Disaster Reduction, University College London, London WC1E 6BT, United Kingdom; Géosciences Rennes, Université de Rennes 1, CNRS, Rennes Cedex CS 35042, France
Recommended Citation:
Cowie P.A.,Scholz C.H.,Roberts G.P.,et al. Viscous roots of active seismogenic faults revealed by geologic slip rate variations[J]. Nature Geoscience,2013-01-01,6(12)