气候变化领域集成服务门户(CCPortal): Mechanical Amorphization of Synthetic Fault Gouges During Rotary-Shear Friction Experiments at Subseismic to Seismic Slip Velocities

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DOI	10.1029/2020JB019956
	Mechanical Amorphization of Synthetic Fault Gouges During Rotary-Shear Friction Experiments at Subseismic to Seismic Slip Velocities
	Kaneki S.; Oohashi K.; Hirono T.; Noda H.
发表日期	2020
ISSN	21699313
卷号	125 期号:10
英文摘要	Although the effects of mechanical amorphization by fault motion on fault rocks have been investigated both in nature and experiments, the relationship between slip processes and the amount of amorphous materials produced remains unclear. We performed rotary-shear friction experiments on synthetic quartz and kaolinite gouges at room temperature, normal stresses of 1 or 3 MPa, slip velocities of 0.001 or 1 m s−1, and displacements of 1–101 m. X-ray diffraction and microscopic observation data revealed that mechanical amorphization in both materials was accompanied by grain-size reduction, particle rounding, and the formation of ultrafine particles. The amount of amorphous materials produced was strongly dependent on mineralogy and total frictional work regardless of slip velocity. Therefore, mechanical amorphization can occur during both coseismic and subseismic slip. Amorphization of ~7 wt% of quartz gouge required 30.33 MJ kg−1 of frictional work, whereas for kaolinite gouge, only 0.77 MJ kg−1 was required, which is consistent with observed preferential amorphization of clay minerals in faults. For kaolinite, up to 6% of frictional work can be used for mechanical amorphization, indicating its potential importance for faulting energetics. Because some kinds of amorphous phyllosilicates release water at lower temperature than crystalline, mechanical amorphization of fault rocks may influence thermochemical pressurization. Gradual weakening of quartz gouge at 0.001 m s−1 slip velocity suggested that <4 wt% of amorphous silica can weaken a fault by amorphous silica-related lubrication. Mechanical amorphization may accelerate pressure solution healing of faults if dissolution can occur under high porous conditions. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	fault gouge; friction experiment; mechanical amorphization
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/187586
作者单位	Disaster Prevention Research Institute, Kyoto University, Uji, Japan; Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan; Graduate School of Science, Osaka University, Toyonaka, Japan
推荐引用方式 GB/T 7714	Kaneki S.,Oohashi K.,Hirono T.,et al. Mechanical Amorphization of Synthetic Fault Gouges During Rotary-Shear Friction Experiments at Subseismic to Seismic Slip Velocities[J],2020,125(10).
APA	Kaneki S.,Oohashi K.,Hirono T.,&Noda H..(2020).Mechanical Amorphization of Synthetic Fault Gouges During Rotary-Shear Friction Experiments at Subseismic to Seismic Slip Velocities.Journal of Geophysical Research: Solid Earth,125(10).
MLA	Kaneki S.,et al."Mechanical Amorphization of Synthetic Fault Gouges During Rotary-Shear Friction Experiments at Subseismic to Seismic Slip Velocities".Journal of Geophysical Research: Solid Earth 125.10(2020).