The tsunami bomb was an attempt during World War II to develop a tectonic weapon that could create destructive tsunamis. The project commenced after US Navy officer E.A. Gibson noticed small waves generated by explosions used to clear coral reefs. The idea was developed by the United States and New Zealand military in a programme code named Project Seal.
Tests were conducted by Professor Thomas Leech, of the University of Auckland, in Whangaparaoa off the coast of Auckland and off New Caledonia between 1944 and 1945. British and US defence chiefs were eager to see it developed, and it was considered potentially as important as the atomic bomb. It was expected to cause massive damage to coastal cities or coastal defences.
The weapon was only tested using small explosions and never on a full scale. 3,700 test explosions were conducted over a seven-month period. The tests revealed that a single explosion would not produce a tsunami, but concluded that a line of 2,000,000 kg (4,400,000 lb) of explosives about 8 km (5.0 mi) off the coast could create a destructive wave.
Details of the experiments codenamed "Project Seal" were released to the public by the Ministry of Foreign Affairs and Trade in 1999 and are available at Archives New Zealand in Wellington and at the Scripps Institution Of Oceanography Archives in San Diego, California.
A 1968 research report sponsored by the US Office of Naval Research addressed this hypothesis of coastal damage due to large explosion-generated waves, and found theoretical and experimental evidence showing it to be relatively inefficient in wave-making potential, with most wave energy dissipated by breaking on the continental shelf before reaching the shore.
No specific targets for the weapon were identified, but in 2013 New Zealand broadcaster and author Ray Waru suggested coastal fortifications in Japan ahead of an invasion of the Japanese home islands.
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- Leech, Thomas D.J (18 December 1950). Project Seal: the generation of waves by means of explosives. Wellington, N.Z.: Department of Scientific and Industrial Research. OCLC 31071831. Retrieved 1 January 2013.
- Bingham, Eugene (25 September 1999). "Tsunami bomb NZ's devastating war secret". New Zealand Herald. Retrieved 2009-12-30.
- Van Dorn, W. G.; LeMéhauté, Bernard; Hwang, Li-San (1968). Final Report : Handbook of Explosion-Generated Water Waves. Volume I – State of the Art. Pasadena: Tetra Tech, Incorporated. Retrieved 2009-12-30.
- Bingham, Eugene (28 September 1999). "Devastating tsunami bomb viable, say experts". New Zealand Herald. Retrieved 2009-12-30.
- Bourke, Emily (3 January 2013). "Military archives show NZ and US conducted secret tsunami bomb tests". Australian Broadcasting Corporation.
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