Generation of Rayleigh waves by underground of nuclear explosions: an examination of the effect of spall impact and site configuration
Description: Thesis. The effect of spall impact, site configuration, and the material properties of rocks at the blast site on the generation of Rayleigh waves by underground nuclear explosions was examined by experimental and computational methods. The hypothesis was that the impact of earth and rock, i.e., spall, falling back after being kicked up by the initial shock wave of an explosion is a source of surface waves observed from explosions. A comparison of amplitudes derived from spall momentum with observed Rayleigh amplitudes at ranges of from 50 to 500 km showed that the spall has sufficient impulse to account for these waves. In the site configuration studies it was found that the strongest signal was produced by a horizontally distributed source placed beneath a mountain, and the weakest signal was produced by a concentrated source placed beneath a flat plain. The horizontal dimension of the source had the biggest effect on the Rayleigh amplitude. Based on laboratory measurements of the mechanical properties of rocks in drill cores from the Boxcar and Gasbuggy sites, calculations were made of the spall impulse and surface displacement profiles from these explosions. The numerically obtained profiles were in reasonable agreement with values inferred from accelerometer data obtained at the sites. (LCL)
Date: July 1, 1973
Creator: Viecelli, J.A.
Partner: UNT Libraries Government Documents Department