 Barnes Wallis' idea was to drop a large, heavy bomb with a hard armoured tip at supersonic speed (as fast as an artillery shell) so that it penetrated the ground like a ten-ton bullet being fired straight down.It was then set to explode underground, ideally to the side of, or underneath, a hardened target.The resulting shock wave from the explosion would then produce force equivalent to that of a 3.6 magnitude earthquake, destroying any nearby structures such as dams, railways, viaducts, etc.