DOI: 10.5194/tc-10-385-2016
Scopus记录号: 2-s2.0-84958966229
论文题名: Tremor during ice-stream stick slip
作者: Lipovsky B ; P ; , Dunham E ; M
刊名: Cryosphere
ISSN: 19940416
出版年: 2016
卷: 10, 期: 1 起始页码: 385
结束页码: 399
语种: 英语
英文关键词: earthquake recurrence
; earthquake swarm
; fault slip
; friction
; glacier dynamics
; GPS
; ice stream
; seismograph
; shear modulus
; spacing
; stick-slip
; subglacial environment
; wave propagation
; Antarctica
; West Antarctica
英文摘要: During the 200 km-scale stick slip of the Whillans Ice Plain (WIP), West Antarctica, seismic tremor episodes occur at the ice–bed interface. We interpret these tremor episodes as swarms of small repeating earthquakes. The earthquakes are evenly spaced in time, and this even spacing gives rise to spectral peaks at integer multiples of the recurrence frequency ∼ 10-20Hz. We conduct numerical simulations of the tremor episodes that include the balance of forces acting on the fault, the evolution of rate-and state-dependent fault friction, and wave propagation from the fault patch to a seismometer located on the ice. The ice slides as an elastic block loaded by the push of the upstream ice, and so the simulated basal fault patch experiences a loading velocity equal to the velocity observed by GPS receivers on the surface of the WIP. By matching synthetic seismograms to observed seismograms, we infer fault patch area ∼ 10m2, bed shear modulus ∼ 20MPa, effective pressure ∼ 10kPa, and frictional state evolution distance ∼ 1μm. Large-scale slip events often occur twice daily, although skipped events have been increasing in frequency over the last decade. The amplitude of tremor (recorded by seismometers on the ice surface) is greater during the double wait time events that follow skipped events. The physical mechanism responsible for these elevated amplitudes may provide a window into near-future subglacial conditions and the processes that occur during ice-stream stagnation. © 2016 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75186
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Department of Geophysics, Stanford University, Stanford, CA, United States; Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, United States
Recommended Citation:
Lipovsky B,P,, Dunham E,et al. Tremor during ice-stream stick slip[J]. Cryosphere,2016-01-01,10(1)