It's funny that some ideas, obvious to express in a language, should be so hard to grasp in another. I think in Portuguese we normally would not use a noun to describe that «water explosion» (although, among children and teenagers kidding in a pool, it is quite normal to jump inside with your body fully folded, in a ball, and say you made a bomba («bomb»)).
If, however, you throw a rock into a pond and it makes a big splash, we'll probably use a verb, saying that it «splashed a lot»: Atirei uma pedra ao lago e salpicou imenso.
In war literature, when describing bombs exploding underwater, it is common to read about «big/tall collumns of foam»: A carga submarina deflagrou erguendo uma enorme coluna de espuma.
Well, I'm not sure I answered your question. Really can't come up with more specific ideas for the moment...