to the sheer strength of the waves. It was calculated by using tsunami run up from Honolulu, Hilo, and the average of stations in California. Even excluding the values given by Hilo (the highest ), the tsunami magnitude is at least 9.1. The earthquake was originally thought to be a strike-slip earthquake, and later a strike slip earthquake with a normal faulting component. These erroneous focal mechanisms were due to a lack of stations recording the earthquake. However, modeling of the S wave, rather than the P wave helped to uncover both the true magnitude of the earthquake, as well as the widely accepted thrusting mechanism. This thrust mechanism is consistent with a subduction earthquake helping to relieve stress on the Aleutian Trench. Tsunami At Unimak Island, tsunami run-up reached . The tsunami earthquake aspect of this event helps to explain a portion of this massive height, however the rest must be attributed to a local submarine landslide. Waves reportedly traveled across the ocean at and measured high, crest to trough. The wave reached Kauai, Hawaii 4.5 hours after the quake, and Hilo, Hawaii 4.9 hours later. In Hilo, 173 died, 163 were injured, 488 buildings were demolished and 936 more were damaged. Witnesses told of waves inundating streets, homes, and storefronts. Many victims were swept out to sea by receding water. The tsunami caused much damage in Maui as well. Waves there demolished 77 homes and many other buildings. The residents of these islands were caught off-guard by the onset of the tsunami due to the inability to transmit warnings from the destroyed posts at Scotch Cap, and the tsunami is known as the April Fools' Day Tsunami in Hawaii because it happened on April 1. The effects of the tsunami also reached Washington, Oregon, and California. The tsunami was unusually powerful for the size of the earthquake. The event was classified as a tsunami earthquake due to the discrepancy between the size of the tsunami and the relatively low surface-wave magnitude. The large-scale destruction prompted the creation of the Seismic Sea Wave Warning System, which became the Pacific Tsunami Warning Center in 1949. See also List of earthquakes in 1946 List of earthquakes in Alaska List of earthquakes in the United States References External links Tsunami Animation: Unimak Island, Aleutian Islands, 1946 – Pacific Tsunami Warning Center 1946 Aleutians Tsunami – Western States Seismic Policy Council Mystery of