EARTH VIBRATIONS FROM A NUCLEAR EXPLOSION IN A SALT DOME
COAST AND GEODETIC SURVEY ROCKVILLE MD
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Recorded earth particle motions in terms of displacements, velocities, and accelerations were near predictions in the distance range of 1.5 to 603 km for the 5 kt SALMON nuclear detonation in a Mississippi salt dome. These motions included measurements from nearby cities and industrial facilities. Scaled earth motions from HE detonations of 500 to 4000 lbs in the unconsolidated shallow sediments were consistently higher than the motions recorded from SALMON. Asymmetric seismic energy propagation was observed with more efficient propagation to the north and south. Apparent velocities of the first arrivals were 1.458 to 6 km from ground zero, east 2.82 kmsec, south 2. 67 kmsec 6 to 100 km, 4.77 kmsec and 100 to 603 km southwest, 8.5 kmsec. The maximum motions were propagated at near 1.9 kmsec. The horizontal resultant vector for first motion was anomalous for three stations with deviations from a radial path of 36.2 to 66 degrees. Equivalent earthquake magnitude from calculated seismic energies was near 5.1 with a source-seismic energy ratio of 0.47 percent.
- Nuclear Weapons