Lahaina Harbor. Maui. Hawaii is the U.S. state that has higher risk for a tsunami. There are at least one year. Every seven years, has one of gradual relevance. On the morning of April 1, 1946, an earthquake with a magnitude of 7.8 occurred in the Aleutian Islands in Alaska. Nearly five hours later, at 7 am, the biggest and most destructive tsunami unprecedented islands claimed the lives of 159 people. Many were curious, including schoolchildren, who ventured into the area coral exposed to large waves, knowing that the tide and receding water nearby were a sign of tsunami. Unable to alert inhabitants. Damage to the property was approximately $ 26 million. On Molokai, the waves were 16.5 m (54 ft) and in a valley of the large island called Pololu, 16.8 m (55 ft). Water in some areas penetrated about 800 m of land. Tsunamis are associated with earthquakes in the ocean and coasts. When an earthquake occurs, the power generated travels in all directions from its source. Detecting a tsunami is very difficult. Tsunamis, being generated by earthquakes traveling at variable speeds. The fastest can reach 645-805 km / h (400-500 mph). In the open ocean, tsunami reaches a minimum height, impossible to notice by vessels surrounding the area. Once you reach the shallow waters recede and form these big waves. The tsunamis strike the coast in a series of waves, the most powerful of them is not the first, nor the last. The tsunami waves that make up the differ widely from those that are generated by winds, no doubt many of us have observed on the beaches. Tsunamis in deep water can have a wavelength greater than 482 km (300 miles) and a duration of one hour.