Effect of water on the frictional behavior of cohesive rocks during earthquakes

Fluid-rock interactions can control earthquake nucleation and the evolution of earthquake sequences. Experimental studies of fault frictional properties in the presence of fluid can provide unique insights into these interactions. We report the first results from experiments performed on cohesive si...

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Bibliographic Details
Published in:Geology (Boulder) 2014-01, Vol.42 (1), p.27-30
Main Authors: Violay, M, Nielsen, S, Gibert, B, Spagnuolo, E, Cavallo, A, Azais, P, Vinciguerra, S, Di Toro, G
Format: Article
Language:English
Subjects:
analog simulation
Asperity
Cohesion
Earth Sciences
Earthquakes
Effects
Environmental Sciences
experimental studies
Experiments
faults
Fluid dynamics
Fluid flow
Friction
gabbros
Geophysics
Global Changes
igneous rocks
laboratory studies
marbles
metamorphic rocks
microgabbro
microstructure
Nucleation
physical models
Physics
plutonic rocks
Rocks
Sciences of the Universe
Seismic phenomena
Seismology
Water
water-rock interaction
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Summary:Fluid-rock interactions can control earthquake nucleation and the evolution of earthquake sequences. Experimental studies of fault frictional properties in the presence of fluid can provide unique insights into these interactions. We report the first results from experiments performed on cohesive silicate-bearing rocks (microgabbro) in the presence of pressurized pore fluids (H2O, drained conditions) at realistic seismic deformation conditions. The experimental data are compared with those recently obtained from carbonate-bearing rocks (Carrara marble). Contrary to theoretical arguments, and consistent with the interpretation of some field observations, we show that frictional melting of a microgabbro develops in the presence of water. In microgabbro, the initial weakening mechanism (flash melting of the asperities) is delayed in the presence of water; conversely, in calcite marble the weakening mechanism (brittle failure of the asperities) is favored. This opposite behavior highlights the importance of host-rock composition in controlling dynamic (frictional) weakening in the presence of water: cohesive carbonate-bearing rocks are more prone to slip in the presence of water, whereas the presence of water might delay or inhibit the rupture nucleation and propagation in cohesive silicate-bearing rocks.
ISSN:0091-7613
1943-2682
DOI:10.1130/G34916.1