Tsunami These are a series of waves usually generated by the movement of the seafloor. These movements are caused by different types of geophysical phenomena such as earthquakes , landslides, and volcanic eruptions. The word tsunami is a Japanese word, represented by two characters: tsu, meaning, "harbor", and nami meaning, "wave". The tsunami waves behave very differently in deep water than in shallow water as their speed is related to the water depth. They frequently occur in the Pacific, where dense oceanic plates slide under the lighter continental plates. When these plates fracture they provide a vertical movement of the seafloor that allows a quick and efficient transfer of energy from the solid earth to the ocean. Source:- https://oceanservice.noaa.gov/