The Sieberg Intensity Scale
The Richter Scale
The Saffir-Simpson Intensity Scale
The Sieberg-Ambraseys Intensity Scale
...volcanic eruptions underwater
Valentine's Day 1993
Canada Day 2006
Valentine's Day 2002
Seek higher ground
Hide in your living room
Go help other people who you think are in danger.
Don't. Just let the waves take you away...
A small wave.
An unusually large sea wave produced by a seaquake or undersea volcanic eruption.
A tsunami is a horrible thing, and I picked this answer because I have nothing else to choose.
A tsunami is what happens when houses are swept off the ground by the wind.