气候变化领域集成服务门户(CCPortal): Flow-to-Friction Transition in Simulated Calcite Gouge: Experiments and Microphysical Modeling

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DOI	10.1029/2020JB019970
	Flow-to-Friction Transition in Simulated Calcite Gouge: Experiments and Microphysical Modeling
	Chen J.; Verberne B.A.; Niemeijer A.R.
发表日期	2020
ISSN	21699313
卷号	125 期号:11
英文摘要	A (micro)physical understanding of the transition from frictional sliding to plastic or viscous flow has long been a challenge for earthquake cycle modeling. We have conducted ring-shear deformation experiments on layers of simulated calcite fault gouge under conditions close to the frictional-to-viscous transition previously established in this material. Constant velocity (v) and v-stepping tests were performed, at 550°C, employing slip rates covering almost 6 orders of magnitude (0.001–300 μm/s). Steady-state sliding transitioned from (strong) v-strengthening, flow-like behavior to v-weakening, frictional behavior, at an apparent “critical” velocity (vcr) of ~0.1 μm/s. Velocity-stepping tests using v < vcr showed “semi-brittle” flow behavior, characterized by high stress sensitivity (“n-value”) and a transient response resembling classical frictional deformation. For v ≥ vcr, gouge deformation is localized in a boundary shear band, while for v < vcr, the gouge is well-compacted, displaying a progressively homogeneous structure as the slip rate decreases. Using mechanical data and post-mortem microstructural observations as a basis, we deduced the controlling shear deformation mechanisms and quantitatively reproduced the steady-state shear strength-velocity profile using an existing micromechanical model. The same model also reproduces the observed transient responses to v-steps within both the flow-like and frictional deformation regimes. We suggest that the flow-to-friction transition strongly relies on fault (micro)structure and constitutes a net opening of transient microporosity with increasing shear strain rate at v < vcr, under normal stress-dependent or “semi-brittle” flow conditions. Our findings shed new insights into the microphysics of earthquake rupture nucleation and dynamic propagation in the brittle-to-ductile transition zone. ©2020. The Authors.
英文关键词	brittle-to-ductile transition; calcite friction; earthquake nucleation; flow-to-friction transition; microphysical model; rock deformation mechanisms
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/187527
作者单位	State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing, China; HPT Laboratory, Department of Earth Sciences, Utrecht University, Utrecht, Netherlands; Faculty of Civil Engineering and Geosciences, Technical University of Delft, Delft, Netherlands; Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
推荐引用方式 GB/T 7714	Chen J.,Verberne B.A.,Niemeijer A.R.. Flow-to-Friction Transition in Simulated Calcite Gouge: Experiments and Microphysical Modeling[J],2020,125(11).
APA	Chen J.,Verberne B.A.,&Niemeijer A.R..(2020).Flow-to-Friction Transition in Simulated Calcite Gouge: Experiments and Microphysical Modeling.Journal of Geophysical Research: Solid Earth,125(11).
MLA	Chen J.,et al."Flow-to-Friction Transition in Simulated Calcite Gouge: Experiments and Microphysical Modeling".Journal of Geophysical Research: Solid Earth 125.11(2020).