Image Database of Geothermal Drill Core Samples in Japan

Abstract

Drill core samples from about 50 surveyed areas in Japan have been reserved in the depository of Geological Survey of Japan. Total length of the core samples reach up to 26.6 km. Core image database is the best way to preserve these images forever and open to public. The database is temporarily uploaded on the website: http://riodb02.ibase.aist.go.jp/drillcore/. The locations of surveyed areas for core samples are shown on the geothermal resources map in the scale of 1:1,000,000. Most surveyed areas are located around volcanic front, and farther areas behind volcanic front show generally lower potential with several exceptions. The thermal features based on maximum temperatures are compared each other by projection on the same diagram. The comparison indicates that potential reservoirs are expected around 250〜350℃ at 500〜2,500 m in depth. The thermal features are also shown as cross-sections of geologic and thermal structures. Important characteristic core samples are chosen from Kyushu, Tohoku and Hokkaido and briefly explained.