The Underwater Nuclear Blast That Shook the Ocean Operation Wahoo was an underwater nuclear detonation test conducted by the United States on May 16, 1958, as part of Operation Hardtack I. The test involved a 9-kiloton nuclear device detonated at a depth of approximately 500 feet (150 meters) in the Pacific Ocean near Enewetak Atoll. The explosion created a massive underwater shockwave, sending a towering water column and radioactive spray into the air. The test was designed to study the effects