When the so-called "Mother of all Bombs" or "MOAB" was unleashed in a remote area of Afghanistan recently, some questioned why it hadn't been used before. The simple fact is that the MOAB is an obliteration bomb; leveling everything in its blast radius. Its predecessor was the "Daisy Cutter" that weighed a mere 15,000 pounds compared to the "MOAB" that weighs nearly 22,000.
The "Daisy Cutter" was originally developed for use in Vietnam to clear landing areas for troop transport helicopters as shown in this picture:
Thus, a bomb like the "MOAB" is restricted to remote areas where civilians can't be harmed to avoid committing war crimes under the Geneva Conventions, to which the U.S. is a signatory.
One last thing. Because the "MOAB" detonates above ground and is not intended to create a cratering of the ground, some question its recent use against ISIS tunnels in Afghanistan, and I agree. We have massive earthquake bombs that would more easily and effectively cause tunnels to collapse. We currently have a 30,000 "Massive Ordnance Penetrator" at are disposal for this very purpose. We also used smaller 5,000 pound earthquake bombs during the first Gulf War to destroy tunnel systems and underground complexes near Baghdad. So, this leads me to think that the real purpose for using the "MOAB" was more about intimidation rather than the destruction of a network of tunnels.
Source of Photo: http://www.psywarrior.com/Blu82HeloLanding.jpg
THE United States has dropped a Massive Ordnance Air Blast Bomb – the largest non-nuclear weapon in its arsenal – on an ISIS tunnel target in Afghanistan: http://www.dailystar.co.uk/news/latest-news/605389/US-non-nuclear-bomb-Massive-Ordnance-Air-Blast-Bomb-ISIS-tunnel-Afghanistan
Daisy Cutter: https://en.wikipedia.org/wiki/BLU-82
Carpet Bombing, Obliteration Bombing: Geneva Convention: https://en.wikipedia.org/wiki/Carpet_bombing
Earthquake Bombs: https://en.wikipedia.org/wiki/Earthquake_bomb