What happens when a bomb goes off underwater? An explosion in air will force air outwards, causing a pressure wave away from the bomb which will spread and disperse. Since, as I understand it, water cannot be compressed, such a pressure wave should be impossible.
My guess is that the bomb forces water outwards, causing a ripple wave and creating a vacuum bubble around the bomb, which, moments later, collapses as the water is sucked back into the vacuum. Is that somewhere near correct?