Contrary to popular belief, a tsunami is not a stronger type of hurricane. A tsunami is caused by an underwater earthquake or volcanic eruption. This disturbance sends a series of waves riding to the shores. However, not every underwater earthquake will create a tsunami. Usually, tsunamis are produced from earthquakes involving convergent continental plates (one plate moves on top of another and pushes the weaker plate beneath it). When these plates shift, they cause some of the most violent and powerful earthquakes and, consequently, some of the most devastating tsunamis, such as the 2004 Sumatra tsunami, which claimed the lives of more than 300,000 people.

From the disturbance's point of origin, waves can reach speeds of more than 450 miles per hour (724 km/h). Tsunamis are not like typical waves that circulate water at the surface. Instead, tsunamis circulate water to the depths of the ocean, which means that they carry a gigantic amount of force and can travel long distances, sometimes more than 1,000 miles (1,609 km). As tsunami waves come within miles of the shoreline, the waves shorten and decrease in speed. For coast guards and boaters, it may appear as though the waves are no threat to the land at all. In fact, the word “tsunami” is a Japanese word for “harbor wave,” which boaters who were far from shore thought them to be. When you are far out on the ocean, a tsunami can appear to be a tidal wave that poses little threat to the shore. However, moments before reaching the shore, tsunami waves slow down and can burst into walls of water more than 100 feet (30 m) high and come crashing mercilessly down on the beach. The tsunami can displace millions of gallons of water, causing some of the worst devastation of any natural disaster.