Geology And How Bunker Busting Bombs Work

The U.S. has conducted aerial strikes on three Iranian Nuclear sites, including Fordow, Natanz and Esfahan, using massive bunker busting bombs.

Experts (and internet communities) have long debated if such a strike would be successful. Experts agreed that bunker busting bombs or missiles previously deployed by Israeli forces would not be sufficient to reach the heavily fortified underground facilities. Only the GBU-57, exclusively operated and deployed by the U.S. Air Force, is large enough

The GBU-57 Massive Ordnance Penetrator (MOP) is a bomb designed to penetrate as deep as possible into soil, rock and concrete before detonating. It “digs” itself into the ground thanks to its reinforced hull, its 30,000 pound (over 13 tons) mass and high kinetic energy at the moment of surface contact.

The GBU-57 has never been used in combat and the only experience origins from testing it in the White Sands Missile Range in New Mexico, where the geology consists of alluvial sediments — a relatively soft material. Based on released information the warhead is able to reach depths of 250 feet (60 meters), with the geological composition and strength of the ground determining how far it will penetrate before detonating and how effectively it will transmit the force of the explosion to damage the target.

The facility of Fordow, hosting the centrifuges needed for uranium enrichment, is buried deep underground in the Zagros Mountains. The facility’s cover was estimated to be around 260 to 290 feet (80 to 90 meters) thick, consisting of limestone and dolostone layers. Depending on the exact composition, grain structure and tectonic deformation, this type of bedrock can surpass the strength of reinforced concrete.

Sources differ on the number of bombs dropped on Fordow. Based on the thick cover, the expected rock types and likely reinforced materials used to build the bunker, it was clear that even if deploying the GBU-57, repeated hits were necessary to ensure maximal damage. Allegedly 4 to 12 “bunker busters” were dropped directly on the facility, with an unspecified number of missiles striking the surroundings.