1991 年 44 巻 3 号 p. 155-164
Tidal fluctuations of groundwater temperature are recognized at Nishiawakura observation well in Okayama Prefecture, Japan. The tidal fluctuations of the temperature are similar to those of the discharge induced by the earth tides, and a little time lag is recognized. Our model which assumes heat transmission between fluctuated groundwater flow and surrounding rocks can qualitatively explain the observed tidal fluctuations of the groundwater temperature, but the model is not enough to explain the tidal amplitude of the groundwater temperature. A careful investigation of groundwater temperature variation at suitable wells would be useful to detect a crustal strain, which is important for earthquake prediction research.