Deep Sea Devastation: What Happens When a Nuclear Bomb Explodes Underwater?

What would happen if a nuclear bomb were detonated underwater? In a similar scenario in 1946, the US Army conducted such a test. The Navy sought to demonstrate that their ships could withstand a nuclear explosion. However, the results were devastating. They placed the bomb roughly 90 feet below the water's surface, arranging their ships around the blast area to assess the explosion's effects. The outcome, however, was terrifying. The ship LSM-60, stationed directly above the bomb, was completely destroyed upon detonation. The surrounding ships sank immediately, and the intense radiation obliterated all remaining vessels in the area.

USS LSM-60

The USS LSM-60 was a medium landing ship used by the United States Navy during World War II. Commissioned in 1944, it played a crucial role in amphibious operations, transporting troops, vehicles, and supplies directly onto enemy shores. Notably, the LSM-60 was involved in Operation Crossroads in 1946, where it was used in atomic bomb tests at Bikini Atoll to study the effects of nuclear explosions on naval vessels. During the underwater explosion test, a powerful blast inflicted significant structural damage and radioactive contamination on the LSM-60, leading to its destruction along with eight other target ships. Its role in both wartime operations and atomic testing solidifies its place in naval history. 

What Happens When a Nuclear Bomb Explodes Underwater?

When a nuclear bomb explodes underwater, it sets off a sequence of catastrophic events with profound implications. The detonation unleashes an intense shockwave that propagates through the water, generating a massive initial blast. This blast creates a rapidly expanding gas bubble as the bomb's energy vaporizes surrounding water, which then collapses under immense pressure, further amplifying the destructive force.

Simultaneously, the explosion releases thermal radiation, superheating the water and causing a steam cloud to rise. The thermal pulse can ignite fires and cause significant damage to anything nearby. The shockwave and resulting bubble collapse produce powerful secondary effects known as cavitation, generating additional shockwaves capable of severely damaging ships, marine life, and underwater structures.

Radioactive material from the bomb mixes with the water, spreading contamination over a wide area. This contamination poses significant environmental and health risks, affecting marine ecosystems and potentially entering the food chain. Additionally, the explosion may induce tsunamis depending on its size and depth, further endangering coastal areas.

Simply put, underwater nuclear explosions create a devastating mix of blast effects, thermal radiation, cavitation, radioactive contamination, and the possibility of tsunamis. These collectively highlight the serious implications of nuclear testing and warfare in oceanic environments, impacting marine ecosystems and coastal areas significantly.