Bunker buster A bunker buster is a bomb designed to penetrate hardened targets or targets buried deep underground . Artillery delivered bombs . Germany . Röchling shell s were bunker - busting artillery shells , developed by German engineer August Cönders , based on the theory of increasing sectional density to improve penetration . They were tested in 1942 and 1943 against the Belgian Fort d ' Aubin - Neufchâteau Aircraft delivered bombs . World War II . United Kingdom . In World War II the British designer Barnes Wallis , already famous for inventing the bouncing - bomb , designed two bombs that would become the conceptual predecessors of modern bunker busters : the five tonne Tallboy and the ten tonne Grand Slam " Earthquake " bombs . The designs were very aerodynamic with a tail which caused them to spin . This allowed them to exceed the speed of sound as they fell from 22 , 000 ft ( 6 , 700 m ) . They had casings of high grade steel , much stronger than the typical WWII bomb so that they would survive hitting a hardened surface , or penetrate deep into the ground . Though these bombs might be thought of as ' bunker busters ' today , in fact the original ' earthquake ' theory was more complex and subtle than simply penetrating a hardened surface . The Earthquake bombs were designed not to strike a target directly , but to impact beside it , penetrate under it , and create a ' camouflet ' or large buried cavern at the same time as delivering a shock wave through the target ' s foundations . The target then collapses into the hole , no matter how hardened it may be . The bombs had strong casings because they needed to travel through rock rather than reinforced concrete , though they could perform equally well against hardened surfaces . In an attack on the Valentin U - Boat pen s at Farge two Grand Slams went through the 15 ft ( 4 . 5 m ) reinforced concrete hardening — equalling or exceeding the best current penetration specifications . The British " Disney " Rocket - Assisted Bomb was another WW2 device to be used against U - boat pens and other super - hardened targets . Devised by Captain Edward Terrell RNVR of the Admiralty ' s Directorate of Miscellaneous Weapons Development it had a streamlined hardened case and weighed some including the rocket assembly . Actual explosive content was about . For accuracy , the bombs had to be dropped precisely from a pre - determined height ( usually ) . They would free - fall for around 30 seconds until , at , the rockets were ignited , causing the tail section to be expelled . The rocket burn lasted for three seconds and added to the bomb ' s speed , giving a final impact speed of , approximately Mach 1 . 29 . Post - war tests demonstrated the bombs were able to penetrate a thick concrete roof , with the predicted ( but untested ) ability to penetrate of concrete . United States . Post war the US added a form of remote guidance to the Tallboy to create the " Tarzon " , a 12 , 000 - pound bomb deployed in the Korean War against an underground command center near Kanggye . Modern . During Operation Desert Storm ( 1991 ) there was a need for a deep penetration bomb similar to the British weapons of WWII , but none of the NATO air forces had such a weapon . As a stop - gap , some were developed over a period of 28 days , using old 8 inch ( 203 mm ) artillery barrels as casings . These bombs weighed over two tons but carried only of high explosive . They were laser - guided and were designated " Guided Bomb Unit - 28 ( GBU - 28 ) " . It was proved to be effective for the intended role . An example of a Russia n bunker buster is the KAB - 1500L - Pr . It is delivered with the Su - 24M and the Su - 27IB aircraft . It is stated to be able to penetrate 10 – 20 m of earth or 2 m of reinforced concrete . The bomb weighs , with being the high explosive penetrating warhead . It is laser guided and has a reported strike accuracy of CEP . The US has a series of custom made bombs to penetrate hardened or deeply buried structures : More recently , the US has developed the 30 , 000 - pound GBU - 57 . Fuzing . The traditional fuze is the same as a classic armor - piercing bomb : a combination of timer and a sturdy dynamic propeller on the rear of the bomb . The fuze is armed when the bomb is released , and detonates when the propeller stops turning and the timer has expired . Modern bunker busters may use the traditional fuze , but some also include a microphone and microcontroller . The microphone listens , and the micro controller counts floors until the bomb breaks through the desired numbers of floors . ATK is working on a Hard Target Void Sensing Fuze ( HTVSF ) for 2000 and 5000 pound weapons to explode when they reach an open space in a deeply buried bunker . Missiles . The extra speed provided by a rocket motor enables greater penetration of a missile - mounted bunker buster warhead . To reach maximum penetration ( impact depth ) , the warhead may consist of a high - density projectile only . Such a warhead carries more energy than a warhead with chemical explosives ( kinetic energy of a projectile at hypervelocity ) . Nuclear . The nuclear bunker buster is the nuclear weapon version of the bunker buster . The non - nuclear component of the weapon is designed to greatly enhance the penetration into soil , rock , or concrete to deliver a nuclear warhead to a target . These weapons would be used to destroy hardened , underground military bunker s buried deep in the ground . In theory , the amount of radioactive nuclear fallout would be reduced from that of a standard , air - burst nuclear detonation because they would have relatively low explosive yield . However , because such weapons necessarily come into contact with large amounts of earth - based debris , they may , under certain circumstances , still generate significant fallout . Warhead yield and weapon design have changed periodically throughout the history of the design of such weapons . An underground explosion releases a larger fraction of its energy into the ground , compared to an explosion at or above the surface which releases most of its energy into the atmosphere .