This grant supports a two year collaborative effort to develop a rotary shear device for studying the rheology of dense granular materials and fault gouge under earthquake conditions. In order to simultaneously subject materials to large slip, fluid confinement, elevated pore pressure, high slip velocity, and high normal stress, the device will combine a commercially available loading and monitoring device together with a PI developed sealed annular cell that will contain the granular material and allow loading under in situ seismic conditions and a servo-controlled hydraulic system that is capable of continuous, monotonous change of slip velocity. Components of the instrument will be assembled at the University of Oklahoma though the final instrument will be housed and maintained at the USGS in Menlo Park, CA. If successful, the device is anticipated to produce novel experimental data that may lead to advances in our understanding of earthquake rupture mechanics.
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