World War II brought the craziest of the inventions that perhaps humanity could ever come up with, with all manner of odd aircraft, tanks, guns, and bombs. When it comes to creative, borderline weird, and downright ridiculous inventions, the British could be considered leaders. One of their leading scientist, engineer, and inventor was Sir Barnes Neville Wallis. He was best known for inventing the bouncing bomb named Upkeep used by the Royal Air Force during Operation Chastise when they destroyed the German dams of the Ruhr Valley. Interestingly, he also had this other invention that was unprecedented: the “Earthquake Bomb.”
During World War II, most bombs were designed to maximize the amount of explosives inside the shell, usually by making the shell thin so that it could be effectively used against unarmored and unfortified targets like railyards, houses, and factories. When used against hardened targets, however, like German bunkers with the reinforced concrete walls as thick as 5 meters, the explosion would not really cause enough damage. If the explosion was just beside it, the explosion would only bounce off the walls, cause a loud noise, and probably hurt the ears of the occupants. Through 15 feet of concrete, even a 2,000 lb bomb would sound like a muffled thump.
An effective way to destroy a fortified structure was by using a shockwave that would instead do most of the heavy lifting instead of depending on the heat and shrapnel. The thing with a shockwave is that it is transmitted poorly through the air, and the better way to utilize it is in contact through the ground, you know, like an earthquake which will shatter rock like glass.
When the realization dawned on Wallis in 1941, he immediately proposed the idea in the form of a 10-ton bomb that would be dropped just beside the target, burrow deep into the ground, before exploding and causing the seismic waves. These waves would target the foundations of the target infrastructure that would be hard, if not impossible, to repair. Usually, a target hit and damaged by an explosion could still be repaired, as only certain parts or areas of it would be damaged. Another possible effect of this was it could create a cavity like a sinkhole causing the collapse of the structure near it.