Structural Control of Hydrothermal System by Gravity Basement

Abstract

The impermeable basement inferred from gravity anomaly affects hydrothermal convection system. Several convenction models are numerically computed incorporating simplified basement structures. It is shown that the four factors of localized heat source, basement relief, topography, and permeability of overburden, control hydrothermal system, and determine temperature distribution. The same numerical method is applied to simulate temperature profiles of the three geothermal wells at the Hohi geothermal area, central Kyushu. These wells are located on an elongated topography and basement relief, and two dimensional modeling can be applied to them. Good matchings are achieved for these models. It is concluded that the basement relief derived from gravity anomaly is accurate enough to be used in constructing regional hydrothermal models, and can be used in assessing geothermal potential.