Structure of the inter-basin transition zone between Dixie Valley and Fairview Valley, Nevada, USA

In 1954, two major earthquakes spaced four minutes apart produced two surface rupture systems: the Fairview Peak fault zone and Dixie Valley fault zone distributed over the area between the Dixie Valley Structural Basin (DVSB) and Fairview Valley Structural Basin (FVSB). The two fault systems display a ten km inter-rupture discontinuity, which this study refers to as the Inter-Basin Transition Zone (IBTZ).;This study offers an interpretation of the structural geometry of the IBTZ based on new gravity data (318 stations) integrated with rupture patterns, GPS strain tensor, seismic focal mechanism, and related geological studies. A new Complete Bouguer Anomaly (CBA) gravity map reveals the basement structural relief in the IBTZ. Northwest gravity gradients and rupture termination alignments were chosen as the approximate structural boundaries of the IBTZ which measures approximately 20 km north to south. An interpretation of basement depths assuming densities associated with Tertiary alluvium and volcanic basin fill over Mesozoic metasedimentary basement indicates the DVSB and FVSB terminate in smaller structural basins. These form a roughly antisymmetric pair of north-south trending, right-stepping graben (3 to 5 km wide and 600-700 m deep), which attenuate in relief toward a central overlap area.;The graben are consistent with the concept of a zone of maximum east-west extension cutting through the IBTZ, which aligns with the southward projection of the maximum east-west extension in western Dixie Valley reported by other studies. The right-overlap area and significant rupture segments associated with the 1954 Fairview Peak-Dixie Valley earthquake sequence seem to be controlled by the interpreted boundaries of the gravity defined IBTZ, which appears to be an anticlinal antithetic accommodation zone with relay ramps.;Analysis of GPS strain tensor, earthquake focal mechanism solutions, and rupture patterns support the influence of northwest-southeast crustal shear across the 60 km wide zone containing the north-south Fairview Peak surface ruptures.;Elevenmile Canyon and Pirouette Mountain geothermal fields are two low temperature geothermal systems located in antisymmetric structural nodes of the IBTZ, where northwest IBTZ boundaries intersect the north-south graben (range-front) faults. We suggest that these intersection zones have potential to facilitate deep convective geothermal flow.