SURFACE MOTION FROM AN UNDERGROUND DETONATION,
STANFORD RESEARCH INST MENLO PARK CA
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Surface and near-surface acceleration and strain were measured on a deep underground nuclear burst Rainier Shot 900 feet 1.7 kt to permit extrapolation of results to nuclear detonations of other yields under different test or employment conditions. Results indicate that a large earth cap, probably including more than one chunk, separated from the mesa over the charge and subsequently fell back into place. The only significant vertical displacement occurred at or near ground zero and reached a maximum of approximately 0.9 feet. Both acceleration and horizontal surface strain measurements suggest that the principal disturbance on the mesa surface was confined to a small region around ground zero however, the measurements on the slope indicate significant earth motion. Velocity data integrated accelerations indicate that the layering characteristics of the medium exert a great influence upon the severity of the ground motion. The displacement-time double-integrated accelerations data at surface zero agrees well with photographic data. In general, the peak displacements indicate that the cap rock moved up and away from surface zero, whereas the permanent displacements on the mesa show that the final positions of the stations are downward and inward toward surface zero, relative to preshot position.
- Nuclear Explosions and Devices (Non-Military)