Magnetic anomalies over the continents

By far most of the magnetic coverage over continents has been made via aircraft. The obvious advantages of the airborne method over ground measurements are the speed and economy of the survey, the coverage of areas that are inaccessible on the ground, and the nature of the data, which are displayed continuously rather than as discrete points along a profile.

Much aeromagnetic work both in the United States and abroad has been conducted by private companies exploring for ore and petroleum. Unfortunately almost none of the data have been published, nor have they been made available to the public.