气候变化领域集成服务门户(CCPortal): Time Dependent Mechanical Crack Closure as a Potential Rapid Source of Post-Seismic Wave Speed Recovery: Insights From Experiments in Carrara Marble

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DOI	10.1029/2020JB021301
	Time Dependent Mechanical Crack Closure as a Potential Rapid Source of Post-Seismic Wave Speed Recovery: Insights From Experiments in Carrara Marble
	Meyer G.G.; Brantut N.; Mitchell T.M.; Meredith P.G.; Plümper O.
发表日期	2021
ISSN	21699313
卷号	126 期号:4
英文摘要	Seismological observations indicate strong variations in wave velocities around faults both co-seismically during earthquakes, and post-seismically. Recovery is commonly associated with a reduction in crack damage. Here, we explore the recovery associated with time-dependent mechanical closure of cracks. We report results from laboratory experiments conducted on dry cores of Carrara marble at room temperature. We deformed cylindrical samples in the semi-brittle regime to induce crack damage before subjecting them to hydrostatic and triaxial stress conditions for extended periods of time while recording dilatancy and wave speeds repeatedly. We report wave speed increases of up to 40% of the damage-induced wave speed drop in samples subject to hydrostatic loading. Moreover, we report the occurrence of significant wave speed increases contemporaneously with time-dependent creep in triaxially loaded samples. Wave speed recovery during creep is only observed below a threshold creep strain rate, a result we interpret as a transition from brittle to plastic creep with decreasing strain rate. We interpret the wave speed increase in terms of reduced crack density and increased contact area within the crack array, and show that around 40% of the total crack surface has to be closed to justify the observed wave speed recoveries. We propose that mechanical crack closure is driven by the viscous relaxation of the bulk rock under the influence of locked-in stresses at low confining pressure, and of the external stresses at higher confining pressure. Our study shows that mechanical crack closure is a significant source of time-dependent wave speed recovery. © 2021. The Authors.
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/187221
作者单位	Department of Earth Sciences, University College London, London, United Kingdom; Department of Earth Sciences, Utrecht University, Utrecht, Netherlands
推荐引用方式 GB/T 7714	Meyer G.G.,Brantut N.,Mitchell T.M.,et al. Time Dependent Mechanical Crack Closure as a Potential Rapid Source of Post-Seismic Wave Speed Recovery: Insights From Experiments in Carrara Marble[J],2021,126(4).
APA	Meyer G.G.,Brantut N.,Mitchell T.M.,Meredith P.G.,&Plümper O..(2021).Time Dependent Mechanical Crack Closure as a Potential Rapid Source of Post-Seismic Wave Speed Recovery: Insights From Experiments in Carrara Marble.Journal of Geophysical Research: Solid Earth,126(4).
MLA	Meyer G.G.,et al."Time Dependent Mechanical Crack Closure as a Potential Rapid Source of Post-Seismic Wave Speed Recovery: Insights From Experiments in Carrara Marble".Journal of Geophysical Research: Solid Earth 126.4(2021).