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Release : 1961
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Book Synopsis Subsurface Motion from a Confined Underground Detonation. Part i by :

Download or read book Subsurface Motion from a Confined Underground Detonation. Part i written by . This book was released on 1961. Available in PDF, EPUB and Kindle. Book excerpt: Particle motion measurements were made within the mesa adjacent to Rainier shot (1.7kt) of Operation Plumbbob on both a horizontal and a vertical radius. Principal information was derived from radial component acceleration data. Horizontal radius data were obtained over a range from 100 feet to 1355 feet from the source; vertical radius data were obtained over a range from 366 feet to the surface at 896 feet. Most of the accelerometers used by Project 26.4b were given set ranges below the actual peak accelerations produced by Rainier. A consequence of this was that many records required use of a nonlinear calibration procedure and a few included peaks truncated by saturation of the recording system. All acceleration data were integrated to particle velocity and displacement information. Peaks were added to truncated records to produce velocity-time data which implied return to zero velocity at a reasonable time after initial motion. Peak horizontal accelerations decay inversely as the fourth power of radial range to about 5g at 500 feet, then progressively as the inverse second and first powers. Peak vertical accelerations decrease as the inverse second power up to the base of the welded tuff (rhyolite) cap rock. Above that point accelerations increase, presumably as a result of reflection phenomena in a medium of decreasing seismic impedance as the surface is approached.