- A tsunami is large wave on the ocean, usually caused by an undersea earthquake, a volcanic eruption, or coastal landslide.
- A tsunami can travel hundreds of miles over the open sea and cause extensive damage when it encounters land.
- Tsunamis are fairly common in Japan.
- As the waves travel to land, they build up to higher and higher heights as the depth of the ocean decreases.
- The speed of tsunami waves depends on ocean depth, not the distance from the source of the wave.
- Tsunami waves can be very long and be as far as one hour apart.
- A tsunami is not a single wave but a series of waves, also known as a wave train.
- Tsunami waves may travel as fast as jet planes over deep waters, only slowing down when reaching shallow waters.