US developed Tsunami Bomb during WW2

The US obviously developed the Atomic Bomb and our excuse for using it has been that it saved countless lives from what would have otherwise been a costly land invasion of Japan. Although if the nuke has not been so persausive, we also had another ace up our sleeves...

(To buy a book on the Japan Invasion, click here.)

The tests were carried out in waters around New Caledonia and Auckland during the Second World War and showed that the weapon was feasible and a series of 10 large offshore blasts could potentially create a 33-foot tsunami capable of inundating a small city.

The top secret operation, code-named "Project Seal", tested the doomsday device as a possible rival to the nuclear bomb. About 3,700 bombs were exploded during the tests, first in New Caledonia and later at Whangaparaoa Peninsula, near Auckland.

I'm assuming that we may have started Tsunami-ing Japan has they not complied with surrender. It does make me wonder though that if 1940s technology could develop a rather sinister weapon like this - what do the world's military's have under wraps that they're not telling us about?