How many tsunamis happen a year?

Hawaii is always at great risk for a tsunami – they get about 1 per year and a severe one every 7 years. The biggest tsunami that occurred Hawaii happened in 1946, the coast of Hilo Island was hit with 30 ft waves at 500 mph. read more

Some few might create tsunamis in the range of a few centimeters. The rare tsunamis that are meters high occur perhaps once every several decades. Tsunamis that create walls of water many meters high occur perhaps once or twice every one or two hundred years. read more

Tsunami's like the one that hit Japan and swept across the Pacific Ocean on Friday only happen about every 15 years. Mega tsunami’s (also called iminami or "purification wave"). Mega tsunami’s have a wave that reaches more than 100 meters (328 feet). read more