Effects of deviatoric stress on undrained pore pressure response to fault slip

Two sides of a fault: Grain-scale analysis of pore pressure control on fault slip.

Pore fluid pressure in a fault zone can be altered by natural processes (e.g., mineral dehydration and thermal pressurization) and industrial operations involving subsurface fluid injection and extraction for the development of energy and water resources. However, the effect of pore pressure change on the stability and slip motion of a preexisting geologic fault remains poorly understood; yet, ...

Change of Pore Fluid Pressure Versus Frictional Coefficient During Fault Slip

Effective normal stress alteration due to pore pressure changes induced by dynamic slip propagation on a plane between dissimilar materials

[1] Recent, detailed examinations of fault zones show that walls of faults are often bordered by materials that are different from each other and from the more uniform material farther away. In addition, they show that the ultracataclastic core of mature fault zones, where slip is concentrated, is less permeable to flow across it than the adjoining material of the damage zone. Inhomogeneous sli...

Pore pressure and poroelasticity effects in Coulomb stress analysis of earthquake interactions

[1] Pore pressure changes are rigorously included in Coulomb stress calculations for fault interaction studies. These are considered changes under undrained conditions for analyzing very short term postseismic response. The assumption that pore pressure is proportional to faultnormal stress leads to the widely used concept of an effective friction coefficient. We provide an exact expression for...

Shear-induced dilatancy of fluid-saturated faults: Experiment and theory

[1] Pore fluid pressure plays an important role in the frictional strength and stability of tectonic faults. We report on laboratory measurements of porosity changes associated with transient increases in shear velocity during frictional sliding within simulated finegrained quartz fault gouge (d50 = 127 mm). Experiments were conducted in a novel true triaxial pressure vessel using the double-di...