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Could a large tsunami happen in the United States?

Large tsunamis have occurred in the United States and will undoubtedly occur again.

Significant earthquakes around the Pacific rim have generated tsunamis that struck Hawaii, Alaska, and the U.S. west coast. One of the largest and most devastating tsunamis that Hawaii has experienced was in 1946 from an earthquake along the Aleutian subduction zone. Runup heights reached a maximum of 33 to 55 feet and killed 159 people. The tsunami generated by the 1964 magnitude 9.2 earthquake in the Gulf of Alaska (Prince William Sound) caused damage and loss of life across the Pacific, including Alaska, Hawaii, California, Oregon, and Washington.

Since the only major tsunami-generating subduction zones in the Atlantic Ocean are along the Caribbean Sea, tsunamis in the Atlantic have been relatively infrequent. The most noteworthy tsunami resulted from the 1929 magnitude 7.3 Grand Banks earthquake near Newfoundland. The maximum tsunami runup was 6 to 23 feet, which was concentrated on the coast of Newfoundland, although it was recorded as far south as South Carolina. A couple of tsunamis reported from Caribbean earthquakes had runups of less than 3 feet.

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