气候变化领域集成服务门户(CCPortal): Tremor during ice-stream stick slip

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DOI	10.5194/tc-10-385-2016
	Tremor during ice-stream stick slip
	Lipovsky B.P.; Dunham E.M.
发表日期	2016
ISSN	19940416
卷号	10 期号:1
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).
学科领域	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
语种	英语
scopus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
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119702
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
推荐引用方式 GB/T 7714	Lipovsky B.P.,Dunham E.M.. Tremor during ice-stream stick slip[J],2016,10(1).
APA	Lipovsky B.P.,&Dunham E.M..(2016).Tremor during ice-stream stick slip.Cryosphere,10(1).
MLA	Lipovsky B.P.,et al."Tremor during ice-stream stick slip".Cryosphere 10.1(2016).