On March 13th the U.S. used one of its large (9.8 ton) MOAB (Massive Ordnance Air Blast) GPS guided smart bomb in combat for the first time. The MOAB was dropped on an ISIL (Islamic State in Iraq and the Levant) tunnel and cave complex in eastern Afghanistan. This area was guarded by hundreds of landmines and explosive traps in addition to several hundred of the Islamic terrorists. Officially known as GBU-43/B, the bomb performed as expected, leaving over a hundred visible dead. Some ISIL men may have been vaporized and others buried deep in the collapsed caves and tunnels. A large explosion likes this creates an overpressure that kills troops deep inside of bunkers. In addition to the shock wave and tunnel collapses the explosion also sucks up all the oxygen in caves and tunnels, asphyxiating those not killed by the blast or overpressure.
MOAB entered service in 2003 and fifteen were built but was never used for fear it would kill nearby civilians. The ISIL complex in Afghanistan was known to be restricted to ISIL members and had become a major storage site for weapons, ammo and bomb making components. It was also a training center, especially for bomb builders. Afghan forces were reluctant to try and take it from the ground because they had suffered a lot of casualties just probing the defenses. Using smart bombs and laser guided missiles could destroy cave and tunnel entrances but not get at the men and material inside. This was the sort of target MOAB was made for. Within hours of the explosion Afghan troops and American special operations forces advanced through the destroyed (by overpressure and blast) minefields and encountered no resistance. Using robots and various sensors it was found that a lot of items stored in those caves was destroyed or buried. Excavating all that will be time consuming and necessary to recover useful information on ISIL operations.
MOAB is not dropped out of bomber but pushed out the back of a SOCOM (Special Operations Command) MC-130E aircraft (or any similar aircraft, like the C-17). The blast can be felt several kilometers away, and the mushroom shaped cloud (that rises to over 3,000 meters/10.000 feet) can be seen more than 40 kilometers away.
MOAB replaced the Vietnam era BLU-82 (Daisy Cutter) bomb, which used a 6.3 ton slurry of ammonium nitrate and powdered aluminum. MOAB uses more powerful tritonal explosives. In addition to a more powerful explosion, MOAB doesn't need a parachute, like the Daisy Cutter, but uses a GPS (like JDAM) and an aerodynamic body glide to and detonate the bomb at a precise area. Thus the MOAB can be dropped from a higher altitude (like outside the range of machine-guns and rifles). The force of a MOAB explosion is sufficient to knock over tanks and kill any people within several hundred meters of the detonation.
Not to be outdone in 2005 Russia revealed it had built a bomb similar to MOAB, but theirs contained 7.1 tons of a more powerful explosive than MOAB used, and that the blast radius of the Russia bomb was twice the size of MOABs’. While MOAB is equivalent to 11 tons of TNT (the benchmark for measuring different explosives), the Russian bomb was said to be equal to 44 tons of TNT. It also appeared, from the Russian test video, that their bomb was a FAE (fuel air explosive). This could be seen from the typical FAE two stage explosion. A Russian video also showed the area surrounding the blast, and the damage was consistent with an FAE explosion, and about as powerful as MOAB. It appears that the Russians were making publicity, not a factual announcement of a new weapon.