Journal ArticleDOI
Ductile creep and compaction: A mechanism for transiently increasing fluid pressure in mostly sealed fault zones
TLDR
In this article, a simple cyclic process is proposed to explain why major strike-slip fault zones, including the San Andreas, are weak, and the cycle adjusts so that no net porosity is created (if the fault zone remains constant width).Abstract:
A simple cyclic process is proposed to explain why major strike-slip fault zones, including the San Andreas, are weak. Field and laboratory studies suggest that the fluid within fault zones is often mostly sealed from that in the surrounding country rock. Ductile creep driven by the difference between fluid pressure and lithostatic pressure within a fault zone leads to compaction that increases fluid pressure. The increased fluid pressure allows frictional failure in earthquakes at shear tractions far below those required when fluid pressure is hydrostatic. The frictional slip associated with earthquakes creates porosity in the fault zone. The cycle adjusts so that no net porosity is created (if the fault zone remains constant width). The fluid pressure within the fault zone reaches long-term dynamic equilibrium with the (hydrostatic) pressure in the country rock. One-dimensional models of this process lead to repeatable and predictable earthquake cycles. However, even modest complexity, such as two parallel fault splays with different pressure histories, will lead to complicated earthquake cycles. Two-dimensional calculations allowed computation of stress and fluid pressure as a function of depth but had complicated behavior with the unacceptable feature that numerical nodes failed one at a time rather than in large earthquakes. A possible way to remove this unphysical feature from the models would be to include a failure law in which the coefficient of friction increases at first with frictional slip, stabilizing the fault, and then decreases with further slip, destabilizing it.read more
Citations
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Journal ArticleDOI
Laboratory-derived friction laws and their application to seismic faulting
TL;DR: In this article, a review of the relationship between friction and the properties of earthquake faults is presented, as well as an interpretation of the friction state variable, including its interpretation as a measure of average asperity contact time and porosity within granular fault gouge.
Journal ArticleDOI
Frictional slip of granite at hydrothermal conditions
TL;DR: In this paper, the authors measured the strength, sliding behavior, and friction constitutive properties of faults at hydrothermal conditions by sliding laboratory granite faults containing a layer of granite powder (simulated gouge).
Journal ArticleDOI
Introduction to Special Section: Mechanical Involvement of Fluids in Faulting
TL;DR: The United States Geological Survey sponsored a Conference on the Mechanical Effects of Fluids in Faulting under the auspices of the National Earthquake Hazards Reduction Program at Fish Camp, California, from June 6 to 10, 1993 as discussed by the authors.
Journal ArticleDOI
Fluid-rock reaction weakening of fault zones
TL;DR: In this article, the presence of weak phyllosilicates may explain the low shear strengths of fault zones if they define well-developed fabrics, and they can contribute directly to reaction softening.
Journal ArticleDOI
Poroelastic rebound along the Landers 1992 earthquake surface rupture
TL;DR: In this article, maps of post-seismic surface displacement after the 1992, Landers, California earthquake, generated by interferometric processing of ERS-1 Synthetic Aperture Radar (SAR) images, reveal effects of various deformation processes near the 1992 surface rupture.
References
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John Conrad Jaeger,N. G. W. Cook +1 more
TL;DR: In this article, Mecanique des roches and Analyse des contraintes were used to construct Elasticite Reference Record (ER) and Elasticite reference record (ER).
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Journal ArticleDOI
The Generation and Compaction of Partially Molten Rock
TL;DR: Uounu et al. as mentioned in this paper derived the equations governing the movement of the melt and the matrix of a partially molten material from the conservation of mass, momentum, and energy using expressions from the theory of mixtures.
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Gilbert Strang,L. B. Freund +1 more
TL;DR: In this article, the authors introduce the concept of applied mathematics and apply it to applied mathematics problems in the context of applied applications. [2]... ].. [3]
Journal ArticleDOI
High-angle reverse faults, fluid-pressure cycling, and mesothermal gold-quartz deposits
TL;DR: In this paper, the authors infer that the vein sets developed near the roofs of active metamorphic/magmatic systems and represent the roots of brittle, high-angle reverse fault systems extending upward through the seismogenic regime.