A tsunami is a large ocean wave caused by sudden motion occurring on the ocean floor. Earthquakes, volcanic eruptions, or underwater landslides are typically the cause of the sudden motion. Tsunamis travel across the open ocean at great speeds and build into large deadly waves in the shallow water of a shoreline. They can also be caused by the impact of large meteorites, which is only rare occurrences.
Most tsunamis are caused by earthquakes generated in a subduction zone. These are the areas where the oceanic plate is being forced down into the mantle due to tectonic forces. The sub ducting plate and the overriding plate then cause an enormous amount of friction.This friction prevents a slow and steady rate of subduction which cause the two plates to become stuck together. As this stuck plate continues to descend into the mantle, the overriding plate begins to undergo a distortion, or a “bulge.” As the plate distorts, it acquires a large amount of energy until it accumulates enough to cause an excess on the amount of friction between the two stuck plates and the overriding plate filled with energy will sort of snap back into its original position. This is the sudden motion that results in the tsunami by giving a huge push to the overlying water. Many people have the idea that tsunamis are a single giant wave; however, tsunamis actually consist of multiple waves known as “train waves.”