The main response of governments around the world to the risk of tsunamis is to set up early warning systems. Oceanic buoys that measure the magnitude of waves passing them. Early warning systems with sirens at beaches and radio broadcasts. In a few places, high sea walls are constructed, but this is only practical to protect specific items. So basically, the only answers we have are those I stated earlier. Sea walls, and "run for your life". A lot of SBI's (silly bugger ideas) have been listed in this thread. (That is not a problem as long as people understand what they are. Speculate all you like, but keep your feet on the ground. There are enough idiots out there already!