I remember watching that documentary of the Canary Island created tsunami. It isn't implausible.

It has happened before but it is rare: Hawaii has sloughed off huge landslides in the prehistoric past that have left evidence all over the Pacific.
https://en.wikipedia.org/wiki/Hilina_Slump https://en.wikipedia.org/wiki/Hilina_Slumphttps://en.wikipedia.org/wiki/Hilina_Slump

However, the mega-tsunami and super-volcano or all the mega-disaster terms that have been coined in the last few years have served little more than rattle the imagination along with metor/comet hits and have captivated movie audiences. The chances of these events happening in mine or yours lifetime are extremely low.

I'd worry more about the "run of the mill" hurricanes, tornadoes, tsunamis, floods and earthquakes. I say that with a bit of cheese...