A tsunami is a series of very long ocean waves, usually triggered by an earthquake. They can travel up to 500 miles per hour when passing through deep ocean water. Knowing the speed of a tsunami can be vital when it comes to predicting when a tsunami will reach land. This information helps people determine evacuation plans for those in the tsunami's path.

Determine the depth of the ocean through which the tsunami is passing to determine its speed. You can find ocean depths at the National Oceanic and Atmospheric Administration website or The World's Oceans website. The depth is represented by "d" in the equation for calculating the tsunami's speed.

Multiply the depth (d) by acceleration due to gravity (g) -- 9.81 meters per second.

The square root of the d x g sum is the speed of the tsunami.