Tsunami is a japanese word with the English translation "harbor wave".

Tsunamis are unrelated to the tides, although they may ride on them.

Tsunamis can be caused by earthquakes, landslides, or meteorite impact.

Tsunamis are shallow-waves water, with long periods and wavelengths.

Wavelengths can be in excess of 100 km, and periods greater than 1 hour.

Shallow water waves move at the Lagrange speed: the square root of the gravitational acceleration times the water depth.