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Abstract

The mechanical response of a fault zone during an earthquake may be controlled by the diffusion of excess heat and fluid pressures generated by frictional heating. In this study a numerical model is formulated which incorporates the effects of frictional heating on the thermal, hydrologic, and mechanical response of a small patch of the failure surface. This model is used to examine the parameters that control the fault response, and to determine their critical range of values where thermal pressurization is significant. The problem has two time scales; a characteristic slip duration and a characteristic time for thermal pressurization. The slip duration is set by the fault geometry. The characteristic time for thermal pressurization is set by the slip rate, friction coefficient, and the thermal and hydraulic characteristics of the medium. Results suggest that the fault width, and hydraulic characteristics of the fault zone and adjacent medium are the primary parameters controlling the mechanical response. For narrow zones with a low porous medium compressibility (