Statistical and Geostatistical Analysis of Temperature Profiles in the Yanaizu-Nishiyama Geothermal Felds, Northeastern Japan

Abstract

In order to reveal characteristics of temperature distribution, temperature profiles in the Yanaizu-Nishiyama geothermal field has been analyzes statistically and geostatistically. Most of the temperature profiles are approximated by the equation, T=a+b./d + c.d. The equation can give a good temperature estimate at deep levels, when all data shallower than 1000m are used. Temperature deviation, which is defined difference between the temperatures measured and estimated by Equation (1) gives a typical variogram in most cases. Only when the variance of temperature deviation is large, a variogram has a local maximum. These statistical and geostatistical characters suggest that kriging should be available for estimating a 3-D temperature distribution.