DOI: 10.1016/j.tecto.2020.228429
论文题名: 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
作者: Kanagawa K. ; Murayama H. ; Sugita A. ; Takahashi M. ; Sawai M. ; Furukawa N. ; Hirose T.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 784 语种: 英语
中文关键词: 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
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. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170616
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
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]. Tectonophysics,2020-01-01,784