ABSTRACT
Although there have been many investigations of fault properties over the past twenty years, obtaining information on the processes and properties within an active fault is still a major challenge, and has been the driver behind several recent, high-profile research initiatives (e.g., the San Andreas Fault Observatory at Depth, or SAFOD). In this talk, I will present results from a series of studies that rely on detailed surface-based methods to collect data that compliment more expensive borehole-based studies. Since 2003, I have used primarily thermal data to characterize the hydraulic properties of the Borax Lake fault, an active normal fault that controls the Borax Lake hydrothermal system. The results of these investigations have provided information on the distribution of permeability in the fault, a detailed picture of the near-surface flow field, and potential insights into thermal-hydro-mechanical processes within the fault zone. Because the hydraulic properties of faults are important inputs to studies in a wide variety of disciplines, the results of these investigations have important implications for petroleum and geothermal reservoir engineering, mining engineering, ore emplacement, disposal of radioactive and hazardous waste, and deep geologic sequestration of carbon dioxide.