PHOTOGRAPHIC MEASUREMENTS OF SURFACE PHENOMENA

The visible surface phenomena of a nominal 30-kt nuclear weapon exploded underwater at a depth of 2000 ft were measured photographically. The direct underwater shock wave produced a slick with a 14,000-ft radius and a spray dome with a 7000ft radius and a central height of 170 ft. The initial velocity of rise of the central portion of the spray dome was 115 ft/sec, which was 33% higher than expected on the basis of high-explosive results. The first bubble pulse produced a spiky second dome that reached a height of 900 ft. Peak air-shock pressures, calculated from shock velocities, indicated an overpressure at Surface Zero (SZ) of 4.43 psi. Large possible errors in measurement make this value questionable. Results indicated that current knowledge of the surface phenomena of deep underwater explosions is inadequate for the prediction of most nuclear-weapon surface effects. (Author)
Report on Operation Wigwam, Project 1.5. (U) Supersedes Rept. no. ITR-1059.