1906 San Francisco earthquake
major earthquake that struck San Francisco and the coast of Northern California
A magnitude 7.9 earthquake struck the coast of Northern California at 05:12 am Pacific Standard Time on Wednesday, April 18, 1906. With a maximum Mercalli intensity of XI (Extreme), it created high-intensity shaking from Eureka on the North Coast to the Salinas Valley, an agricultural region to the south of the San Francisco Bay Area.
Extensive fires soon broke out in San Francisco and lasted for several days. More than 3,000 people died and over 80% of the city was destroyed. The event is remembered as the deadliest earthquake in the history of the United States. The death toll remains the greatest loss of life from a natural disaster in California's history and high on the list of worst American disasters, natural or man-made.
Tectonic setting
The San Andreas Fault is a continental transform fault that forms part of the tectonic boundary between the Pacific plate and the North American plate. The strike-slip fault is characterized by mainly lateral motion in a dextral sense, where the western (Pacific) plate moves northward relative to the eastern (North American) plate. This fault runs the length of California from the Salton Sea in the south to Cape Mendocino in the north, a distance of about 810 miles (1,300 km). The maximum observed surface displacement was about 20 feet (6 m); geodetic measurements show displacements of up to 28 feet (8.5 m).
Begin with the source’s own compact description: “1906 San Francisco earthquake” is major earthquake that struck San Francisco and the coast of Northern California. The dossier treats that line as a proposition to test through Francisco, earthquake and major, not as a finished interpretation.
Why this record matters
The phrase “major earthquake that struck San Francisco and the coast of Northern California” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 21, 2026. The linked authority identifier is Q211386. The Library of Congress control number is sh2003006458. Authority coordinates are 37.750, -122.550. 1 of 2 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1906.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “1906 San Francisco earthquake”, its source revision and the description used here.
- Expand the search: follow 1906 San Francisco earthquake primary sources, 1906 San Francisco earthquake archive and Francisco research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “1906 San Francisco earthquake”?
- What terminology or title could unlock a more precise catalogue search?
- Which cited source is closest to the event, object or claim?
Search terms from this dossier
This entry incorporates text from “1906 San Francisco earthquake” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.