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6.2: Tsunami!

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    • 6.2.1: The Easter Weekend Tsunami of 1964
      The warning about a cataclysmic earthquake on the Cascadia Subduction Zone has a mythical cast to it as if the Earth could not, in fact, shudder and gyrate in the way scientists have stated it would. But this doomsday scenario is based on an actual subduction-zone earthquake that wracked southern Alaska without warning on Good Friday, March 27, 1964. Alaska is not a heavily populated state, of course, and it had even fewer people in 1964 than it does now.
    • 6.2.2: Other Tsunamis in the Pacific Northwest
      The 1964 tsunami was the most damaging to strike the Pacific Northwest in recorded history, but it was not the only one. Tide-gauge records show that subduction-zone earthquakes in the Aleutian Islands generated tsunamis that were detected in Tofino and Victoria, B.C., Neah Bay, Washington, and Crescent City, California. A larger tsunami resulted from the 1960 earthquake in southern Chile of M9.5, the largest of the twentieth century.
    • 6.2.3: Some Facts about Tsunamis
      First, a tsunami is not a tidal wave. Tides are caused by the attraction between the Moon and Earth, and tsunamis are completely unrelated. If a tsunami arrived at the same time as a high tide, its effects would be worse than if it arrived at low tide, because the wave could travel farther onto the land. Another term is seismic sea wave. This is correct for most tsunamis, but not all, for tsunamis can be generated by submarine volcanic eruptions or submarine landslides.
    • 6.2.4: Tsunami Sounds
      Most observers of a great tsunami are so horrified that they remember only what they saw rather than what they heard. However, Jerry Eaton, a seismologist with the USGS, was at a bridge across the Wailuku River in Hilo, Hawaii, on the night of May 22, 1960, as a tsunami from a monster earthquake in Chile approached the city. Eaton heard “an ominous noise, a faint rumble like a distant train, that came from the darkness far out in Hilo Bay. Two minutes later, … the noise became deafening.”
    • 6.2.5: Tsunami Warning Systems
      The tsunami at Crescent City struck more than four hours after the earthquake. Loss of communication with Alaska delayed the issuance of a tsunami advisory for nearly an hour and a half after the earthquake, and the advisory was not upgraded to a warning until two hours and twenty minutes after the earthquake—about the time the first wave was striking the north end of Vancouver Island.
    • 6.2.6: Tsunami Hazard Maps
      Following the 1992 Cape Mendocino Earthquake, the California Governor’s Office of Emergency Services and the Federal Emergency Management Agency (FEMA) funded a study of the effects of an earthquake of M 8.4 on the Cascadia Subduction Zone for the 150-mile distance across Humboldt and Del Norte counties between Cape Mendocino and Cape Blanco, Oregon. This was published by the California Division of Mines and Geology as Toppozada et al. (1995).
    • 6.2.7: Seiches
      A fascinating subculture in Seattle and, to a lesser extent, in Portland, comprises people who live on the water in houseboats, with the largest number on Lake Union in Seattle. This is not inexpensive living; recent real-estate listings were from half a million to nearly a million dollars for a floating home. There are enough houseboaters to have their own neighborhood community council called the Floating Homes Association. People who live on dry land are known as “uplanders".

    This page titled 6.2: Tsunami! is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Robert S. Yeats (Open Oregon State) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.