Most tsunamis occur in the Pacific Ocean along the Ring of Fire. Up to 80 percent of tsunamis occur within this geologically active area. Earthquakes and volcanoes are common and cause tectonic shifts that result in tsunamis.
When an earthquake occurs under the ocean, water is rapidly displaced. This sudden movement of water causes enormous waves to form and travel toward land. Tsunamis can travel up to 500 mph, leaving very little time to alert people in coastal areas. At this speed, a tsunami can cross the entire Pacific Ocean within a day. Large tsunamis have a height of up to 100 feet of water and cause enormous destruction when they make landfall.