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Government or official record

1959 Hebgen Lake Earthquake

U.S. Geological Survey

Where this source supports the record

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

  1. Natural disasters · 17 August 1959

    The Hebgen Lake Earthquake and Madison Canyon Slide

    Madison Canyon landslide and Earthquake Lake · United States

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    Why editors use it here

    Official earthquake parameters, location, shaking, landslides, and casualty context.

    1. Quick read

      Near midnight on 17 August 1959, a magnitude 7.3 earthquake struck west of Yellowstone National Park.

      Reviewed 26 July 2026
    2. Trigger and conditions

      Normal faulting suddenly displaced the crust beneath the Madison Valley.

      Reviewed 26 July 2026
    3. Uncertainty

      Modern USGS magnitude is commonly 7.3, while older sources list 7.5 because measurement methods changed.

      Reviewed 26 July 2026
    4. Why it matters

      Hebgen Lake was not one hazard but a chain: fault rupture produced shaking, water oscillation, dam damage, landslide, isolation, and new flooding risk.

      Reviewed 26 July 2026