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Government or official record

The 1906 earthquake and a century of progress in understanding earthquakes and their hazards

U.S. Geological Survey

Cross-File evidence ledger

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 · 18–21 April 1906

    The 1906 San Francisco Earthquake and Fires

    San Francisco and the San Andreas Fault rupture zone · United States

    Open File evidence →
    Why editors use it here

    USGS synthesis of losses, the investigation, and the event’s scientific legacy.

    1. Quick read

      At 5:12 a.m.

      Reviewed 24 July 2026
    2. Trigger and conditions

      The Pacific and North American plates slipped along the San Andreas Fault.

      Reviewed 24 July 2026
    3. Uncertainty

      Contemporary official counts substantially understated deaths, particularly among marginalized and transient residents.

      Reviewed 24 July 2026
    4. Why it matters

      The disaster remains a powerful example of cascading risk: a geologic event became an urban fire and housing emergency because critical systems failed together.

      Reviewed 24 July 2026