DOI: 10.1016/j.tecto.2020.228377
论文题名: Frictional properties of actinolite-chlorite gouge at hydrothermal conditions
作者: Okamoto A.S. ; Niemeijer A.R. ; Takeshita T. ; Verberne B.A. ; Spiers C.J.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 779 语种: 英语
中文关键词: Actinolite
; Chlorite
; Earthquake
; Friction
; Megathrust
; Subduction
英文关键词: Earthquakes
; Fault slips
; Hardening
; Linear regression
; Metamorphic rocks
; Shear flow
; Temperature
; Actinolite
; Chlorite
; Coefficient of frictions
; Hydrothermal conditions
; Megathrust
; Multiple linear regressions
; Subduction
; Subduction zone seismogenesis
; Friction
; chlorite
; deformation
; earthquake event
; fault gouge
; fault slip
; friction
; hydrothermal system
; shear zone
; subduction zone
; thrust
英文摘要: Exhumed subduction zones frequently show widespread actinolite-chlorite (Act-Chl) dominated compositions, suggesting that this may play an important role in controlling megathrust fault slip. We investigate the frictional behavior of simulated Act-Chl (85:15) gouge mixtures derived from natural mafic metamorphic rocks, under hydrothermal conditions using a ring shear deformation apparatus. Experiments were performed at effective normal stresses (σn eff) of 50–200 MPa, pore fluid pressures (Pf) of 50–200 MPa, at temperatures (T) of 23–600 °C. In each experiment we applied a shear displacement (x) of ~10 mm at a constant sliding velocity (v) of 10 μm/s, followed by v-stepping in the range 0.3–100 μm/s, and slide-hold-slide (SHS) tests with hold times (t) ranging from 3 s to 3000 s. We quantified the rate- and state-dependent friction parameter (a-b), and investigated the effect of t on fault healing (Δμpk). The results showed no effects of temperature on the coefficient of friction (μ ≈ 0.6–0.7), or on (a-b), with some experiments showing persistent, displacement-hardening or -weakening trends. Nonetheless, effects of v and of normal stress (σn = σn eff + Pf) on (a-b) fall into three temperature regimes: (1) T = 23–100 °C, (2) T = 200–400 °C, and (3) T = 500–600 °C. In Regimes (1) and (3), (a-b) > 0 for all conditions tested, whereas in Regime (2), (a-b) ≤ 0, at σn eff = Pf = 50 MPa and v = 0.3–3 μm/s. We discuss on the origin of persistent displacement-hardening or -weakening trends observed, and assess the implications of our data for subduction zone seismogenesis. Extrapolation of (a-b)-data using multiple linear regression suggests that high pore pressure ratios (>0.9) are needed to promote seismogenesis in faults cutting actinolite-chlorite compositions. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170671
Appears in Collections: 气候变化与战略
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作者单位: Department of Natural History Sciences, Graduate School of Sciences, Hokkaido University, Sapporo, 060-0810, Japan; Department of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, CD 3584, Netherlands; Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan
Recommended Citation:
Okamoto A.S.,Niemeijer A.R.,Takeshita T.,et al. Frictional properties of actinolite-chlorite gouge at hydrothermal conditions[J]. Tectonophysics,2020-01-01,779