九州中部地域の放熱量と熱水上昇を考慮した地殻上層の温度

抄録

There are many active and dormant volcanoes in central Kyushu, Japan. Many fumaroles and hot springs also exist in connection with the volcanoes and they are in a higher than 2 HFU heat flow zone. The distribution of average heat flow values by convective heat transfer such as hot springs and fumaroles was obtained for fifty small blocks (about 20 km×20 km) in order to clarify the detailed pattern of heat discharge at the earth’s surface. Such average heat flow values amount to several to 12 HFU in the blocks which include active geothermal areas. Therefore, it is necessary to consider the effect of upwelling hot water in the underground temperature calculation for the place where convective heat transfer dominates. The temperatures obtained by such a method generally exceed 150℃ at 5 km deep in volcanic and geothermal areas in central Kyushu. Furthermore, the temperatures around Beppu hot spring, Kuju valcano, Aso volcano and Unzen volcano amount to 300℃ at the same depth.