There is no 1 size of nuclear bombs. No bomb that has been detonated thus far would be capable of it I don't think, but I believe Russia has some huge 100 mega tonne nuke that they have never detonated a full one of. 50 mega tonnes has been done and i'm pretty confident there is no hole anywhere near going through earths crust.
RE: Detonating a Nuclear Bomb at the Bottom of the Ocean