The underwater nuclear explosion

This underwater nuclear explosion was conducted by the United States in 1958. The explosion was part of a series of experimental nuclear explosions called Operation Hardtack I.
Location: United States nuclear test site in the Pacific Ocean near Inuit Atoll and Bikini Atoll (now the Marshall Islands).
Explosion power:
Wahoo: approximately 9 kilotons.
Umbrella: approximately 8 kilotons.
Which can usually show its destructive power about three kilometers from a city