35. 地球熱学 : 第16報 日本海における海洋底地殼熱流量(1)

Terrestrial heat flow has been determined at 30 localities in the Japan Sea. The average value of observed heat flow, 2.03×10-6cal/cm2 sec is higher than the world average. Though the heat flow is generally high the following features seem to exist; (a) a zone of slightly low values (1.8-2.0×lO-6cal/cm2 sec) runs in the middle of the Japan Sea roughly parallel to the Japanese island arc; (b) a region with heat flow less than 1.5×1O-6cal/cm2sec exists north of the Sado Island. However, these observations must be tested with further data. Possible effect of annual variation of bottom water temperature on the observed heat flow was examined. When the amplitude of the annual variation is 0.02℃, the expected disturbance is about 0.1×10-6cal/cm2sec.日本海の地殼熱流量観測は舞鶴海洋気象台観測船「清風丸」により着手され,1964年日本海のほぼ全域に亘り30点の観測を行なつた.その平均値は2.03μcal/cm2secという異常に高い値であるが,日本列島に沿つて日本海中央部を走る他の部分よりやや低い熱流量を示す地帯,佐渡ケ島東北方のほぼ陸上の平均値に近い地域などの微細構造が見られるようである.より立入つた議論は1965年の諸種の観測結果を待つものであるが,日本海高熱流量のある程度の部分は新第三紀以降の火山活動によつてまかなわれうるかも知れない