Waves can also form when a rapid shift in ocean water
is caused by underwater earthquakes, landslides,
or meteors that hit the ocean.
These waves, called tsunami, can travel at speeds of
800 kilometers per hour (500 miles per hour).
Although their height in the deep ocean is usually very
small, when a tsunami reaches the coastline, the wave
slows down which causes the water to pile up, creating
a much taller wave.
Many people caught in a tsunami have no warning of
its approach.
Tsunami warning systems are important for protecting
for coastal areas and low-lying countries