Tsunami (pronounced tsoo-nah-mee) is a combination of the Japanese words tsu, meaning harbor, and nami, meaning wave. Tsunamis are powerful waves that are caused by underwater volcanic eruptions, earthquakes, and even rare meteors. Tsunamis form when the underwater eruptions or earthquakes release a large amount of energy. Just like a rock makes ripples in a pond, the force ripples outwards into a small waves, about 3 feet tall and moving over 500 mph. Once they near shore, the energy compresses the wave, making it taller and slowing it down. When a tsunami hits shore, it causes destruction that reaches over 1 mile inland! Then, the wave recedes, pulling all the debris with it.