BULLETIN OF THE AMERICAN ASSOCIATION OF PETROLEUM GEOLOGISTS 
VOL. 18, NO. 1 (SANUARY, 1934), PP. 63-68, 3 FIGS. 
RADIOACTIVITY OF SOIL GASES! 
LYNN G. HOWELL? 
Houston, Texas 
ABSTRACT 
The Alpha-ray activity of the radon in the gases drawn from the soil was measured 
by means of a Wulf-type electroscope having a ro-liter ionization chamber. The method 
of making the measurements is described. Indications that a fair sample of gases was 
obtained at a station were found by repeating measurements at the station on separate 
days. However, there are some conditions under which repeated measurements may 
not check. A typical line survey in the Gulf Coast region shows large variations in 
radioactivity of the gases in the soil. Similar variations are found in a faulted region 
where there seems to be little hope of correlating the positions of high radioactivity with 
the positions of the faults; this agrees with the work of Botset and Weaver. 
INTRODUCTION 
Radioactive minerals are found distributed throughout the upper 
crust of the earth and are thought to be concentrated for the most 
part in a limited layer (1) of the order of tens of kilometers in thick- 
ness. Due to the presence of these minerals in the earth, a knowledge 
of the processes of radioactivity has been of great value in geophysics, 
especially in connection with the accounting for the generation of 
heat in the earth and with calculations of the ages of the various layers 
in the earth’s crust. 
In applied geophysics the properties of radioactive minerals have 
been of importance mainly in the location of the radioactive ores 
themselves. However, Ambronn (2), Link and Schober (3), and Muel- 
ler (4) have made surveys of the content of radon in the soil gases over 
subsurface features of the type represented by faults, in the close 
neighborhood of which an increase in radon content was found. Bogo- 
javlensky (5) has made surveys of the intensity of penetrating rays 
coming from the radioactive minerals in the top layer of the earth and 
has reported finding radiations many times more penetrating than 
the known radiations from radioactive substances. These results can 
hardly be considered as well established. Bogojavlensky (6) has also 
claimed to have found an increase in intensity over pools of oil in 
1 Read before the Geophysics Division of the Association at the Houston meeting, 
March 24, 1933. 
2 Geophysics research department, Humble Oil and Refining Company. Intro- 
duced by Ll. W. Blau. 
3 Parenthetical numbers refer to Bibliography at end of this article. 
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