FYI, tidal waves and tsunami are the same things, whatever their initial cause. But the term "tidal wave" is now generally discouraged because some people see it and think tides are involved, which they aren't.

Not to spoil any of the fun, but... the mega-tsunami from the Canary Islands that was the beginning post of this thread may not really be much of a possibility. Many scientists believe that tsunami are quite localized, and aren't likely to be capable of sustaining that much power across a large ocean.

But it is an interesting theory. If it happened, the sharks would certainly have a field day, wouldn't they?

Sue