Three-Dimensional Gravity Modeling of the Geologic Structure of Long Valley Caldera

摘要: A 48-mGal gravity low coincides with Long Valley caldera and is mainly attributed to low-density fill. Gravity measurements by Unocal Geothermal have been integrated U.S. Geological Survey data, vastly improving station coverage throughout the caldera. strong regional trend isostasy. “best fitting” (based on control of basement densities) Airy-Heiskanen isostatic model was used for correction. three-dimensional, multiple-unit modeling program iterative capabilities developed residual gravity. The density structure vicinity modeled 22 discrete units, most which were based geologic units. Information from drill hole lithologies, surface geology, structural geology interpretations constrain model. Some important points revealed three-dimensional are that (1) volume ejected magma associated Bishop Tuff eruption greater than previously thought, (2) strongly influenced precaldera topography extensions major, active faults, (3) main west ring fracture coincident Inyo Domes-Mono Craters system, (4) a relatively region probably underlies caldera, (5) silicic chamber may underlie Devils Postpile.