Death is by asphyxiation. Bodies were probably in caves.
Death is by concussion & flying debris, mostly.
We used to drop 1/4 lb. blocks of TNT off Namo Bridge north of Danang to deter NVA frogmen. The concussive effect is more pronounced in the much denser water. (of course, 11,000 lbs explosive vs 1/4 lb also is a factor... ;-) .. )
Obama probably paid for the bases construction in the first place