Acehtsunami

On May 19, 2011 landslideat Porcupine Bay, Washington produced a small tsunami. The tsunami traveled across the Spokane River, generating strong waves on the opposite shore that damaged a camp. Landslides in the United States take place in all 50 States. The core regions of landslide occurrence and potential are the coastal and mountainous areas of California, Oregon, and Washington, the States comprising the inter mountain west, and the mountainous and hilly regions of the Eastern United States. Alaska and Hawaii also experience all types of landslides.

In 1958, a much larger landslide produced a tsunami with the world’s highest known run-up in Lituya BayAlaska. On the night of July 9, 1958 an earthquake along the Fair-weather Fault in the Alaska Panhandle loosened about 40 million cubic yards (30.6 million cubic meters) of rock high above the northeastern shore of Lituya Bay. This mass of rock plunged from an altitude of approximately 3000 feet (914 meters) down into the waters of Gilbert Inlet.

The impact generated a local tsunami that crashed against the southwest shoreline of Gilbert Inlet. The wave hit with such power that it swept completely over the spur of land that separates Gilbert Inlet from the main body of Lituya Bay. The wave then continued down the entire length of Lituya Bay, over La Chaussee Spit and into the Gulf of Alaska. The force of the wave removed all trees and vegetation from elevations as high as 1720 feet(524 meters) above sea level. Millions of trees were uprooted and swept away by the wave. This is the highest wave that has ever been known.