Abstract
A decade ago, it would have been the rare geophysicist indeed who would have predicted that his specialty was destined to become a major topic of discussion between such world political leaders as Presidents Eisenhower and Kennedy, Prime Minister Macmillan of Great Britain, and Chairman Khrushchev of the USSR. Yet this has come to pass during the past six years, for in 1958 there started the continuing round of international negotiations directed towards the creation of an effective underground test-ban treaty. During the conduct of these negotiations, it has been repeatedly necessary to assess the current state-of-the-art in seismology and its sister geophysical sciences, for the only detectable signals known to propagate for several hundreds to thousands of miles from underground nuclear tests are seismic in nature. With the United States policy being only to seek an underground-test-ban agreement incorporating strong safeguards against acts of bad faith, it is important that the political safe-guards be backed up by those of a geophysical nature.