An example of a deep underwater explosion is the WAHOO test, which was carried out in 1958 as part of Operation Hardtack. The nuclear device was detonated at a depth of 500 ft (150 m) in deep water. There was little evidence of a fireball. The spray dome rose to a height of 900 ft (270 m). Gas from the bubble broke through the spray dome to form jets which shot out in all directions and reached heights of up to 1,700 ft (520 m). The base surge at its maximum size was 2.5 mi (4.0 km) in diameter and 1,000 ft (300 m) high.
The heights of surface waves generated by deep underwater explosions are greater because more energy is delivered to the water. Deep underwater explosions are thus particularly able to damage coastal areas, because surface waves increase in height as they move over shallow water, and can flood the land beyond the shoreline. Many of the theories and concepts about these waves are similar to those that are applicable to other types of surface waves, in particular, tsunamis, and waves generated by the fall of a meteor.
If a deep underwater explosion occurs at a sufficient depth, the rising gas bubble can over expand because the gas pressure falls below the pressure of the surrounding water. This causes the bubble to collapse, which causes a second shock wave and bubble expansion. This may be repeated, though there are unlikely to be more than three expansions. An example is the WIGWAM test, which was carried out in 1955. The nuclear device was detonated at a depth of 2,000 ft (610 m).