NORMAL GEOTHERMAL GRADIENT 105 


I00-1,000 I00-2,000 I00—3,000 
Feet Feet Feet 
Birmingham 0.00914 0.00955 = 
Grass Valley 0.00593 0.00569 0.00537 
Ames 0.00695 0.00731 = 
Houghton 0.00771 — — 
Franklin Furnace 0.00362 — = 
Lonetree 0.01578 0.01654 0.01806 
Astoria 0.01503 0.01615 0.01656 
Moclips 0.00985 0.01239 0.01342 
Seattle 0.00929 0.00971 — 
b 0.00926 0.01105 0.01335 
1/b 108.04 90.51 74.89 
Comparison of these values with the corresponding values in 
Tables I, II, and III, shows that the mean gradients recorded in 
the tables are determined almost entirely by the much larger values 
of the gradients found in most of the oil-bearing areas. 
TABLE IV 
Ratios oF GRADIENTS 
2,000/ 1,000 3,000/ 1,000 4,000/1,000 Remarks 
n 97 55 20 
m 1.0523 1.0928 1.1928 Table I 
r 0.0927 0.1197 0.1829 
fo 0.0094 0.0161 0.0409 
b 0.01614 0.01676 0.01830 
1/b 61.95 59-65 54-65 
n 95 Table II 
m 1.0417 
r 0.0793 
fo 0.0081 
b 0.01598 
1/b 62.58 
n 41 19 3 Table III 
m 0.9838 0.9944 1.0407 
r ° 0.0753 ° 
To 0.0005 0.0173 0.0502 
b 0.01977 0.01999 0.02110 
1/b 50.57 50.03 47-40 
n 30 18 4 Table III 
1.0074 1.1104 1.2122 
fr 0.0842 0.0721 0.0818 
To 0.0135 0.0170 0.0409 
b 0.01766 0.01787 0.01950 
1/b 56.63 55-97 51-27 
n 38 Table III 
m 1.0850 
ta 0.0669 
To 0.0108 
b 0.01746 
1/6 57.28 
765, 
