Frictional properties of megathrust fault gouges at low sliding velocities; new data on effects of normal stress and temperature

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doi: 10.1016/j.jsg.2011.12.001
Author(s): den Hartog, Sabine A. M.; Peach, Colin J.; de Winter, D. A. Matthijs; Spiers, Christopher J.; Shimamoto, Toshihiko
Author Affiliation(s): Primary:
Utrecht University, Department of Earth Sciences, Utrecht, Netherlands
Hiroshima University, Japan
Volume Title: Physico-chemical processes in seismic faults
Volume Author(s): Di Toro, Giulio, editor; Ferri, Fabio; Mitchell, Thomas M.; Mittempergher, Silvia; Pennacchioni, Giorgio
Source: Physico-chemical processes in seismic faults, edited by Giulio Di Toro, Fabio Ferri, Thomas M. Mitchell, Silvia Mittempergher and Giorgio Pennacchioni. Journal of Structural Geology, Vol.38, p.156-171. Publisher: Elsevier, Oxford, International. ISSN: 0191-8141 CODEN: JSGEDY
Note: In English. 89 refs.; illus., incl. 1 table
Summary: Friction data used in modelling studies of subduction zone seismogenesis are often poorly representative of in situ conditions. We investigated the influence of in situ effective stresses and temperatures on the frictional properties of (simulated) fault gouges, prepared either from Nankai ODP material or illite shale, at sliding velocities approaching those relevant for earthquake nucleation and SSEs. Biaxial (double direct shear) experiments were performed at room temperature, normal stresses of 5-30 MPa, and sliding velocities of 0.16-18 µm/s. All materials exhibited velocity strengthening under these conditions, along with an increase in the friction coefficient and slip hardening rate with increasing normal stress. Illite gouge showed increased velocity strengthening towards higher normal stresses. The effect of temperature was investigated by means of ring shear experiments on illite gouge at 200-300°C, an effective normal stress of 170 MPa, a pore-fluid pressure of 100 MPa and sliding velocities of 1-100 µm/s. These experiments showed a transition from velocity strengthening to velocity weakening at ∼250°C. Our results provide a possible explanation for the updip seismogenic limit within subduction zone megathrusts and imply an enhanced tendency for earthquake nucleation and SSEs at low effective normal stresses. Abstract Copyright (2012) Elsevier, B.V.
Year of Publication: 2012
Research Program: ODP Ocean Drilling Program
Key Words: 16 Structural Geology; Clastic rocks; Clay minerals; Earthquakes; Experimental studies; Faults; Friction; Gouge; High pressure; Illite; Instruments; Leg 190; Nankai Trough; North Pacific; Northwest Pacific; ODP Site 1174; Ocean Drilling Program; Pacific Ocean; Physical models; Pressure; Sedimentary rocks; Seismicity; Shale; Sheet silicates; Silicates; Smectite; Stress; Subduction zones; Techniques; Temperature; Thrust faults; Velocity; Weak rocks; West Pacific
Coordinates: N322000 N322100 E1345800 E1345700
Record ID: 2012067862
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands