气候变化领域集成服务门户(CCPortal): Weakening of quartz rocks at subseismic slip rates due to frictional heating, but not to lubrication by wear materials of hydrated amorphous silica or silica gel

CCPortal

DOI	10.1016/j.tecto.2020.228429
	Weakening of quartz rocks at subseismic slip rates due to frictional heating, but not to lubrication by wear materials of hydrated amorphous silica or silica gel
	Kanagawa K.; Murayama H.; Sugita A.; Takahashi M.; Sawai M.; Furukawa N.; Hirose T.
发表日期	2020
ISSN	00401951
卷号	784
英文摘要	In order to clarify the weakening mechanism of quartz rocks at subseismic slip rates of 0.1–10 cm/s, we conducted two series of rotary-shear friction experiments at a normal stress of 1.5 MPa and equivalent slip rates (Veq) of 0.1–10 cm/s; one on intact agate controlling background temperature (TBG) and atmosphere, and the other on intact agate and silica-gel gouge monitoring temperature (T) adjacent to the slip surface or the gouge layer. In the former experiments at Veq = 1 cm/s, agate samples at room TBG showed similar steady-state friction coefficients (μss = 0.62–0.63) irrespective of humid or dry condition in the latter case of which hydration of amorphous wear materials was hampered, while agate sample at TBG = 100 °C exhibited weakening to μss ≈ 0.35. In the latter experiments, μss of both intact agate and silica-gel gouge decreased with increasing Veq from 0.6–0.7 at Veq = 0.1 cm/s to 0.03–0.16 at Veq = 10 cm/s, while the maximum T increased with increasing Veq from 25–28 °C at Veq = 0.1 cm/s to 88–93 °C at Veq = 10 cm/s. Spikes of high friction followed by T maxima and subsequent weakening suggest that slip at strong asperity contacts induced frictional heat, which in turn resulted in weakening. These two series of friction experiments indicate that the frictional strength of quartz rocks at subseismic slip rates is controlled by temperature, which increases by frictional heating, but not by wear materials of hydrated amorphous silica or silica gel. Indentation strength of quartz is much higher than that of other common rock-forming minerals so that much more amount of frictional heat would be induced at asperity contacts in quartz rocks than in other rocks, which is likely responsible for weakening of quartz rocks at subseismic slip rates. © 2020 Elsevier B.V.
关键词	Agate Frictional heating Silica gel Subseismic slip rates Weakening
英文关键词	Atmospheric temperature; Hydration; Quartz; Rocks; Silica gel; Slip forming; Wear of materials; Amorphous silica; Asperity contacts; Background temperature; Friction coefficients; Friction experiments; Frictional heating; Frictional strength; Rock-forming minerals; Friction; amorphous medium; asperity; friction; heating; hydration; lubricant; quartz; silica; slip rate
语种	英语
来源期刊	Tectonophysics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/207783
作者单位	Department of Earth Sciences, Chiba University, Japan; Research Institute of Earthquake and Volcano Geology, Geological Survey of Japan, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Japan
推荐引用方式 GB/T 7714	Kanagawa K.,Murayama H.,Sugita A.,et al. Weakening of quartz rocks at subseismic slip rates due to frictional heating, but not to lubrication by wear materials of hydrated amorphous silica or silica gel[J],2020,784.
APA	Kanagawa K..,Murayama H..,Sugita A..,Takahashi M..,Sawai M..,...&Hirose T..(2020).Weakening of quartz rocks at subseismic slip rates due to frictional heating, but not to lubrication by wear materials of hydrated amorphous silica or silica gel.Tectonophysics,784.
MLA	Kanagawa K.,et al."Weakening of quartz rocks at subseismic slip rates due to frictional heating, but not to lubrication by wear materials of hydrated amorphous silica or silica gel".Tectonophysics 784(2020).