Tsunami bomb?

Kiwi author and film-maker Ray Waru claims in his latest book 'Secrets and Treasures', that New Zealand and the US carried out secret tests to create a so called "tsunami bomb" during WW2.

During the operation "Project Seal", apparently around 3,700 bombs were exploded off Whangaparaoa Peninsula in Auckland and in New Caledonia. At the time, this destructive device was seen as a possible alternative to the nuclear bomb.

Ref: AWNS-19090204-6-4, Sir George Grey Special Collections
Waru's research for his book is based on military files from national archives. He has stated that the project  started in 1944 after US naval officer E A Gibson observed, that the blasts used to clear coral reefs around Pacific Islands also created large waves.

The records were released in 1999 and are available at Archives New Zealand Te Rua Mahara o Te Kāwanatanga  in Wellington and at the Scripps Institution Of Oceanography Archives in San Diego, California.

Ref: AWNS-19250709-41-1, Sir George Grey Special Collections
The project was cancelled  in early 1945, although New Zealand authorities apparently continued to produce reports on the experiments into the 1950s. The report concluded that single explosions would not be effective enough on their own. Instead around 2 million kilograms of explosives located about 8km inland would be required, to create a giant wave capable of inundating a small city.