Griggs and Teller first suggested underground nuclear testing in early 1956 to reduce dependence on weather conditions, which had made scheduling of atmospheric tests difficult. Subsequent underground testing at the Nevada Test Site has shown added advantages by elimination of radioactive fallout, by improvements in economy, instrumentation, public safety, and scientific experimentation. In particular, the ability to test underground provided the basis for the Limited Test Ban Treaty signed on August 5, 1963.
Geology is a critical factor in the appraisal of nuclear test sites from the standpoints of availability of testing media, public safety, and experimental suitability. Extensive testing programs require large tracts having peculiar geological properties and constitute a natural resource. In regard to public safety, possible hazards of ground-water contamination, and damage from ground shock to population centers are of paramount importance. Judging the suitability of terrane for individual experiments poses problems in ground-water distribution, detailed rock distribution and structure, and most important, in predicting the behavior of the test medium during and after the detonation: how it will expand, fracture, and contract; how the explosion-produced cavity will fill with rock debris and water; how the medium will accept and confine the radioactive products of the explosion.
In addition, the application of geology to underground nuclear testing is providing background data that can be extended to peaceful applications of nuclear explosives such as excavation, block caving in mines, reservoir fracturing, and earthquake studies.