کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4733274 1640539 2012 16 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Frictional properties of megathrust fault gouges at low sliding velocities: New data on effects of normal stress and temperature
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Frictional properties of megathrust fault gouges at low sliding velocities: New data on effects of normal stress and temperature
چکیده انگلیسی

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.


► New data on frictional behaviour of (simulated) subduction zone megathrust gouges.
► Smectite and illite gouges used to address different depth ranges.
► Velocity strengthening in all cases, but weakening in illite gouge at T > 250 °C.
► Illite data offer explanation for updip seismogenic limit in subduction zones.
► Enhancement of unstable slip at low effective normal stress in all materials.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Geology - Volume 38, May 2012, Pages 156–171
نویسندگان
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