Aeroradioactivity survey and related surface geology of parts of the Los Angeles region, California (ARMS-I).

A recent airborne gamma radiation survey in the Los Angeles region, California, shows a moderate range in the levels of natural radioactivity. The lower levels can be related to lowland alluvium and the higher levels can be related to consolidated rocks. The highest radioactivity is associated with granitic intrusions and Tertiary volcanic rocks. The survey is nearly 2800 square miles in area and was made by the U» S. Geological Survey in cooperation with the Division of Biology and Medicine, U. S. Atomic Energy Commission. Continuous radioactivity profiles were obtained with scintillation counting equipment at approximately 500 ft above the ground on parallel north-south flight lines spaced 1 mile apart. A map of aeroradioactivity levels was prepared from the profiles.