How a Tsunami is caused
A tsunami is a series of large waves generated by an abrupt movement on the ocean floor that can result from an earthquake. Tsunami's vary in size caused by the size of the earth quake and how close to the shore it is.
The Indonesian Tsunami was the most deadly tsunami of all time, the earth quake magnitude was a 9. There were 283,100 deaths. This Tsunami was on Dec 26th, 2004