Underground Structure Delineated from Gravity and AGG Data Analysis in the Hohi Geothermal Area, Central Kyushu, Japan

Abstract

The Hohi geothermal area is located in the central Kyushu, Japan. Many geothermal fields, hot springs and the geothermal power plants (Otake, Hatchobaru and Takigami) are included in this area. Many geothermal explorations have been conducted in this area since 1960. The gravity data which is measured by many institute, company and university was recorded in some gravity database. Moreover, an airborne gravity gradiometry (AGG) survey was conducted by the Japan Oil, Gas and Metals National Corporation (JOGMEC) in 2012. The underground density structure is estimated by the gravity and AGG data inversion analysis. This result is integrated with the other geological, geophysical and geochemical data on the GIS software. Finally, the conceptual hydrothermal model is estimated by the integrated interpretation using GIS software.