An Updated Geothermal Resources Map of the Tohoku Volcanic Arc, Japan

A geothermal resources map of the Tohoku volcanic arc was compiled at 1:1,000,000 scale to allow a better understanding of the geothermal resources and geothermal heat sources of the area, from geology and hot spring geochemistry. The map was created using "ARC/INFO". Some interesting features in the distribution pattern of the geothermal resources are indicated. Most high temperature resource areas (hot spring temperature > 90?C) are in and around Quaternary volcanic terrains with few exceptions. The volcanic front is delineated by the N-S trending eastern margin volcanoes. High potential geothermal resources are related to Quaternary volcanoes and/or concealed intrusive bodies, the most likely resource for geothermal electric generation. However, medium temperature resources areas (hot spring temperature; 42-90?C, geochemical temperature > 150?C) occur outside of Quaternary volcanic terrains, and are roughly arranged on NW-SE trending zones extending west from the volcanic front. This implies that these areas are heated by deep circulation of meteoric water along deep fracture zones from conductive heat transfer through highly conductive rock units. These areas could be regarded as identified potential fields for further geothermal exploration. However, geothermal exploration has already proved that most of these areas contain only medium enthalpy hydrothermal water (around 200?C), which is not enough for electricity generation. Medium to low temperature resources areas occur in late Neogene to Quaternary sedimentary basins, and are categorized as deep-seated hot water resources in sedimentary basins of non-volcanic terrain. This resources map is correlated with the distribution maps of heat discharge by hot springs, and depths to basement from gravity. Developed high temperature resources areas correspond to high heat discharging areas of hot springs and shallow basement. This suggests that these areas are heated actively by fluid circulation in Tertiary and Quaternary formations, and also heated by conductive heat transfer in pre-Tertiary basement.

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Field Value
Citation Date 2000-01-01T00:00:00

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Original ID 10a23e2a-397b-4565-9e7f-5ec69298f91d
Index Date 2015-11-18T19:08:18
Original Format ISO-USGIN
Original Version 1.2


Name Shiro Tamanyu, Masaaki Takahashi, Yasuaki Murata, Keiji Kimbara, Masayori Kawamura, Humiharu Yamaguchi and Takeo Matsunami
Organization World Geothermal Congress

Geographic Extent

North Bound 90
South Bound -90
East Bound 180
West Bound -180