I was caught up in a Tsunami back in 2010 and they need to be taken very seriously, even minor ones like the one we experienced.

We were in the Galapagos on our boat when we were woken at 4.00 am by someone banging on the side of the boat. It was one of our companions from another boat and the harbour master. They told us there had been an earthquake in Chile, over 3000 miles away, and a Tsunami was expected to arrive in the Galapagos in 4 to 5 hours time (Tsunami waves travel at close to the speed of sound, in water, so around 700 mph). We were ORDERED to leave the harbour immediately as even though the wave was expected to be small it was expected that the water would get sucked out and any boats still in the harbour would probably be damaged.

We headed out along with maybe 50 other boats and all headed for the deepest water we could reach in the time available before the predicted arrival. We all lined up facing the south east motoring slowly forward until we heard from the harbour master that the wave had arrived and that the harbour was still closed.

We never felt a thing as the wave was only about 4-5 foot high and it just got lost in the ocean swell but back in the harbour it was chaos. All the water had been sucked out and any boats left there had either hit the bottom or in many cases their anchors had dragged and lots of boats had piled up together.

When we were eventually allowed back in the water was still sluicing around and the depth would change by 6-7 ft in a few seconds. This continued for several days.

Anyway, what I'm saying is... Tsunami warnings need to be taken very seriously as even a minor one can cause a lot of damage.

See my wife's blog written at the time here... http://sailingjeannius.blogspot.com.es/2010/02/day-53-galapagos-270210.html and a video (not very dramatic) here https://www.youtube.com/watch?v=V0r97yLlaDw