Finally, How well would a submerged sub handle a tsunami?
It wouldn't even notice it. My friend was on a boat about 10-15miles out from Phuket when the Tsunami hit. She actually saw the "Ripple" pass them, and realised what it was. She is Japanese, and they are hot on this. She called a friend to check if they could look at a seismic website to see if it was reported, and got captain to radio shore. both came back negative. She wasn't convinced and tried calling shore again, this time there was no reply.
Away from shore, where there is deep water a tsunami is not dangerous.