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Government or official record

The Great Alaskan Earthquake, March 27, 1964

Alaska Division of Geological & Geophysical Surveys

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Where this source supports the record

Each entry separates the File’s editorial relevance note from its exact, section-level claims. A bibliography link without a direct claim is labeled plainly.

  1. Natural disasters · 27 March 1964

    The 1964 Great Alaska Earthquake and Tsunami

    Prince William Sound rupture zone and south-central Alaska · United States

    Open File evidence →
    Why editors use it here

    Contemporary state geological publication documenting the earthquake, ground failure, tsunami, and affected Alaska communities.

    1. Quick read

      A magnitude 9.2 earthquake ruptured the Alaska–Aleutian subduction zone for roughly four and a half minutes, making it the most powerful earthquake recorded in United States history.

      Reviewed 24 July 2026
    2. Trigger and conditions

      The Pacific Plate thrust beneath the North American Plate, abruptly displacing an immense section of the seafloor and coastline.

      Reviewed 24 July 2026
    3. Uncertainty

      Fatality totals vary slightly by source depending on whether indirect deaths and distant tsunami losses are included.

      Reviewed 24 July 2026
    4. Why it matters

      The event made cascading coastal risk visible at continental scale.

      Reviewed 24 July 2026