气候变化领域集成服务门户(CCPortal): Plastic Faulting in Ice

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DOI	10.1029/2019JB018749
	Plastic Faulting in Ice
	Golding N.; Durham W.B.; Prior D.J.; Stern L.A.
发表日期	2020
ISSN	21699313
卷号	125 期号:5
英文摘要	Plastic faulting is a brittle-like failure phenomenon exhibited by water ice and several other rock types under confinement. It is suspected to be the mechanism of deep earthquakes and extreme cases of shear localization in shallow rocks. Unlike ordinary Coulombic failure, plastic faulting is characterized by a pressure-independent failure strength and fault plane oriented 45° to maximum principal stress. To research the question of how the instability initiates, we conducted over 50 constant-displacement-rate experiments on polycrystalline ice (phases Ih and II) near the brittle-to-ductile (B-D) transition, at confining pressures P = 0–300 MPa, applied strain rates (Formula presented.) = 5 × 10−5 – 7 × 10−3 s−1, temperatures T = 105–233 K, and mean grain sizes d = 0.25–1.18 mm. We find that (1) the width of the B-D transition in variable space is vanishingly narrow, to the point of appearing as a crossover, (2) a plastic fault plane, once formed, is not a zone of subsequent weakness, (3) distributed ice I→II phase transformation in small amounts (<1 vol%) shows no causal relationship to subsequent failure, and (4) plastic faulting also occurs in ice II. We hypothesize that the elusive nucleating “trigger” parallels that of metals and ceramics undergoing severe plastic deformation, wherein transient local structural rearrangement occurs, in turn causing material strength to drop to a level sufficiently low, in a volume sufficiently large, that adiabatic instability is nucleated. Our results do not require and often are inconsistent with phase transformation. Plastic faulting may therefore be available to all solids undergoing severe deformation, and its appearance in so few is simply the result of insufficiently extreme conditions. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	deep earthquakes; high-pressure fracture; nanocrystallinity; phase transformation; severe plastic deformation; transformational faulting
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187853
作者单位	Earth, Atmospheric and Planetary Sciences Department, Massachusetts Institute of Technology, Cambridge, MA, United States; Department of Geology, University of Otago, Dunedin, New Zealand; U.S. Geological Survey, Menlo Park, CA, United States
推荐引用方式 GB/T 7714	Golding N.,Durham W.B.,Prior D.J.,et al. Plastic Faulting in Ice[J],2020,125(5).
APA	Golding N.,Durham W.B.,Prior D.J.,&Stern L.A..(2020).Plastic Faulting in Ice.Journal of Geophysical Research: Solid Earth,125(5).
MLA	Golding N.,et al."Plastic Faulting in Ice".Journal of Geophysical Research: Solid Earth 125.5(2020).