TWA 800 broke apart in the air due to an explosion. We're not sure what happened to MH370, but it seems possible that it flew until the fuel ran out, and then glided down to the sea surface, perhaps keeping the wings more-or-less intact.
I'm not sure what to make of the georesonance story. I will say that, if they're right, then they are going to have a lot of business in the future. If they're wrong, they may be committing corporate suicide to make such a public claim. Time will tell soon enough, I hope.