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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Mitchell, Thomas
University College London
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (11/11 displayed)
- 2021ESHRE guideline: medically assisted reproduction in patients with a viral infection/diseasecitations
- 2018Mineralogical control on thermal damage and the presence of a thermal Kaiser effect during temperature-cycling experiments
- 2018Quantifying the effect of core plug edge effects on porosity and permeability under uniaxial and triaxial loading conditions
- 2018Low-Frequency Measurements of Seismic Velocity and Attenuation in Antigorite Serpentinite
- 2018Fault Reactivation at the Brittle-Ductile Transition
- 2017Mineralogical control on thermal damage and the presence of a thermal Kaiser effect during temperature-cycling experiments
- 2016The effect of fluids on the frictional behavior of calcite gouge
- 2013Deformation band-like defects as possible precursors to microfracture planes, resulting in the generation of nanopowders on simulated fault planes
- 2013Strain localization in experimentally sheared gouge layers
- 2012Frictional processes in volcanic conduits
- 2011Ultra-low co-seismic stiffness of fault rocks at seismogenic (8-11 km) depth
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document
The effect of fluids on the frictional behavior of calcite gouge
Abstract
The presence of fluids in fault zones affects the faults' strength and the nucleation and propagation of earthquakes due to mechanical or physico-chemical weakening effects. To better understand the effect of pore fluids on the frictional behavior of gouge-bearing faults, a series of intermediate- to high-velocity experiments was conducted using the Phv rotary-shear apparatus (Kochi Core Center, Japan) equipped with a servo-controlled pore-fluid pressure system. Calcite gouge was sheared up to several meters displacement at room-humidity (dry) and water-saturated conditions. The pore-fluid factor, λ=pf/σn, ranged from 0.15 to 0.7 and the effective normal stress, σn,eff=σn-pf, from 1 to 12 MPa. Sheared samples were analyzed using scanning electron microscopy and Raman spectroscopy. The steady-state shear stress is lower for saturated than for dry gouges sliding at V=1 mm/s, possibly due to higher intergranular lubrication and/or accelerated subcritical crack growth, as evidenced also by the observed higher degree of compaction. At V=1 m/s, dry gouges show a pronounced strengthening phase preceding the onset of dynamic weakening; saturated gouges weaken abruptly. The higher λ, the lower the peak and steady-state shear stress, but -counterintuitively- the less localized deformation. Degree of weakening and localization might be influenced by insufficient drainage at high λ. In undrained experiments, the shear stress is slightly decreased likely due to thermal pressurization of the pore fluid, but the onset of dynamic weakening is not accelerated, indicating that dynamic weakening is due to more efficient mechanisms. For example, amorphous carbon may lubricate the slip surfaces of dry and saturated calcite gouges and cause dynamic weakening, yet Raman spectra only show the presence of disordered carbon on the principal slip surface. Furthermore, the presence of small recrystallized grains suggests that strain accommodation during steady-state slip might occur by non-frictional processes, such as grain-boundary sliding aided by diffusion creep....