Earthquake or explosion? The science of nuclear test detection

This article, which follows up on the December 1965 Proceedings of the IEEE special issue on nuclear test detection, outlines the problems of underground detection and identification, offers some background in geophysics that the nonspecialist needs to get a perspective on the niceties of the engineering problems, cites some of the criteria whereby underground events are discriminated, and assesses the present state of the art. It concludes with a description of LASA, the largest seismic array ever built, and speculates on the possible political effects of the recent scientific and technical developments.