DOI: 10.1002/grl.50216
论文题名: Simulations of tremor-related creep reveal a weak crustal root of the San Andreas Fault
作者: Johnson K.M. ; Shelly D.R. ; Bradley A.M.
刊名: Geophysical Research Letters
ISSN: 0094-9198
EISSN: 1944-8929
出版年: 2013
卷: 40, 期: 7 起始页码: 1300
结束页码: 1305
语种: 英语
英文关键词: fault creep
; friction
Scopus关键词: Effective normal stress
; Fault creep
; Frictional properties
; Large earthquakes
; Neutral stability
; San Andreas fault
; Spatiotemporal evolution
; Transient creeps
; Earthquakes
; Friction
; Strike-slip faults
; Structural geology
; Tectonics
; Transport properties
; Creep
; coseismic process
; creep
; crustal root
; earthquake magnitude
; earthquake rupture
; friction
; San Andreas Fault
; San Simeon earthquake 2003
; spatiotemporal analysis
; stress
; California
; Parkfield
; San Andreas
; United States
英文摘要: Deep aseismic roots of faults play a critical role in transferring tectonic loads to shallower, brittle crustal faults that rupture in large earthquakes. Yet, until the recent discovery of deep tremor and creep, direct inference of the physical properties of lower-crustal fault roots has remained elusive. Observations of tremor near Parkfield, CA provide the first evidence for present-day localized slip on the deep extension of the San Andreas Fault and triggered transient creep events. We develop numerical simulations of fault slip to show that the spatiotemporal evolution of triggered tremor near Parkfield is consistent with triggered fault creep governed by laboratory-derived friction laws between depths of 20-35 km on the fault. Simulated creep and observed tremor northwest of Parkfield nearly ceased for 20-30 days in response to small coseismic stress changes of order 104 Pa from the 2003 M6.5 San Simeon Earthquake. Simulated afterslip and observed tremor following the 2004 M6.0 Parkfield earthquake show a coseismically induced pulse of rapid creep and tremor lasting for 1 day followed by a longer 30 day period of sustained accelerated rates due to propagation of shallow afterslip into the lower crust. These creep responses require very low effective normal stress of ~1 MPa on the deep San Andreas Fault and near-neutral-stability frictional properties expected for gabbroic lower-crustal rock. Key Points Transient tremor is driven by deep triggered fault creep Deep San Andreas Fault creeps at low effective normal stress of order 1 MPa Deep San Andreas Fault creeps at near neutral stability friction ©2013. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876927049&doi=10.1002%2fgrl.50216&partnerID=40&md5=726179428c0005893a60e0cd207596f0
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/6462
Appears in Collections: 气候减缓与适应
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作者单位: Department of Geological Sciences, Indiana University, 1001 E. 10th St., Bloomington, IN 47405, United States
Recommended Citation:
Johnson K.M.,Shelly D.R.,Bradley A.M.. Simulations of tremor-related creep reveal a weak crustal root of the San Andreas Fault[J]. Geophysical Research Letters,2013-01-01,40(7).