Appendix A. Seismological Monitoring of the World's First Nuclear Detonation—The Trinity Shot of 16 July 1945

Abstract

Seismology played a modest role in the Trinity test, thereby establishing, at the very birth of the “atomic age,” a mutual interaction between seismology and nuclear testing that would become of increasing significance to both technologies as the century progressed. Because the Trinity “gadget” was designed to be an atmospherically detonated military weapon for which principal damage effects were expected to be air blast and accompanying ground shock of intensities heretofore unexplored, extensive new effects data were needed to plan military applications. When the need for a full-scale test of the implosion design became clear by late 1944, Los Alamos scientists began to devise field experiments to measure both air blast and ground shock. Also, they wanted to estimate how each would scale with explosive energy release (yield), range, and height of burst within a principal target area (nominally, within about 20 km of ground zero).