Study of the Underground Temperature Gradients of Several Wells at Arima Spar District, near Kobe, Japan

Abstract

The underground temperature gradients with reference to the ten wells bored at Arima spar district near Kobe were studied.
Each well bored as deep as 160 meters at shallowest and 300 meters at deepest from the ground surface respectively. The temperatures were found to be 73°C. at lowest and 133°C, at highest.
Average temperature gradient was found, from calculation, to be 11.7°C. per 30 m. depth.
An isothermal map was made at the depth of 120 m., according to the measuring results of the underground temperature at each point.
In consequence, it was found that in the area surrounded by the 50°C. isothermal contour there existed places where the temperatures were higher than 50°C. so that the author attained the conclusion that temperatures above 50°C. will be expected in the area within the 50°C. thermal contour at the depth of 120 m. This conclusion will probably be applicable to the whole Arima spar district as far as the isothermal map concerns.