All Types of Tsunamis Local Tsunami. A local tsunami is a tsunami that causes damage in relatively close proximity to the tsunami-causing Regional Tsunami. A regional tsunami is one that causes damage from 100 km to 1,000 km from the underwater event that Distant Tsunami. A distant tsunami,
The earthquakes that caused these tsunamis are: Prince William Sound, Alaska, 1964, magnitude 9.2; Chile, 1960, magnitude 9.5; Alaska, 1946, magnitude 7.3; Puerto Rico/Mona Rift, 1918, magnitude 7.3 to 7.5; Virgin Islands, 1867, magnitude undetermined; Cascadia, 1700, magnitude 9; and Puget Sound, 900, magnitude 7.5. Map not to scale. Tsunami, catastrophic ocean wave usually caused by a submarine earthquake, by a landslide, or by a volcanic eruption. In deep water it travels as fast as 800 km (500 miles) per hour, with enormous wavelengths of more than 500 km (310 miles) but small wave amplitudes of about 30 to 60 cm (1 to 2 feet). Tsunami "Wave Train" Many people have the mistaken belief that tsunamis are single waves. They are not. Instead tsunamis are "wave trains" consisting of multiple waves. The chart on this page is a tidal gauge record from Onagawa, Japan beginning at the time of the 1960 Chile earthquake. There are two main types of tsunamis: local tsunamis and distant tsunamis. Local tsunamis are relatively small and occur near the source of the earthquake, volcanic eruption, or landslide that generated them. The most common cause of a tsunami is sea floor uplift associated with an earthquake. Tsunamis are also triggered by landslides into or under the water surface, and can be generated by volcanic activity and meteorite impacts. Tsunamis range in size from inches to over a hundred feet. The results suggest that New Zealand can expect a tsunami of 16.4 feet (5 m) approximately every 77 years, with a wave of at least 49.2 feet (15 m) approximately every 580 years. Tsunamis over 3.3