When I visited Japan last year, on my first day I was sitting near a river watching some people play baseball when there was an announcement broadcast over some loudspeakers. I sat through it, not understanding anything, and then it changed to English. It was a tsunami warning and it said to keep away from the Yodo River, which was the river I was sitting beside.
Back at the hotel room, on TV I saw the map of Japan in the corner of the screen on every channel. The coastline was colour-coded according to predicted rise in sea level caused by an earthquake in Chile, and most of it was flashing red.
As it happened, the rise in sea level was minimal, and the next morning the map was still on screens, but with only parts of the coastline highlighted. I wondered at the time why Japan had such a sensitive warning system for tidal waves. I know now. A very sad day.