Geophysical Exploration in the U.S. National Parks

Results from several dozen geophysical surveys at national parks in the United States are summarized here. Illustrations from both succesfful and unsuccessful surveys show the advantages and limitations of geophysical exploration. Ground-penetrating radar and magnetometer surveys have been particularly suitable at sites on the coastal plain of the eastern U.S. While filled cellars can be quite easy to locate, a thinner scatter of rubble from a structure can be difficult to isolate. Cities provide almost impossible conditions for the success of a survey. Accumulations of debris in pits can be located, but privies and wells appear to be more difficult to find. Prehistoric features are almost always harder to locate than historical features; geological features can be too apparent at some sites