Heat flow data analysis

Six hundred and eighty‐seven heat flow data from more than 780 individual determinations and estimations were compiled. Of these, 634 data were analyzed. The range of the present heat flow per unit area is approximately 0 to 8 µcal/cm 2 sec. The world's arithmetic mean is 1.62, and the standard deviation of a datum is 1.21. The data do not seem to form any simple distribution. Since the sampling is poor and biased, a weighted mean technique is developed. On the basis of three assumptions, the world's average heat flow per unit area was found to be 1.5 ± 10 per cent at 95 per cent confidence. This is significantly higher than the value 1.2 suggested in 1954. There is no simple dependence of heat flow per unit area on latitude and longitude. A spherical harmonic analysis indicates that all the coefficients of the harmonics are at least an order of magnitude less than the mean of about 1.5. Heat flow and geological parameters, as well as difficulties in heat flow research and sources of heat, are briefly discussed. The purpose of this study is to summarize all the available data in a comprehensive list with extensive bibliographies and to set up computer programs for data analysis that can be used in the future.