West Napa Fault
Open-knowledge reference entry
The West Napa Fault is a 57 km (35 mi) long geologic fault in Napa County, in the North Bay region of the San Francisco Bay Area in northern California. It is believed to be the northern extension of the Calaveras Fault in the East Bay region.
It has been mapped as a Late Pleistocene-Holocene active fault, and is considered to be predominantly a right lateral strike-slip fault. The fault was discovered in 1976 by Gene Boudreau, a ground water drilling specialist from Sebastopol. In 2023 there was data showing that the West Napa Fault is actually nine miles longer than previously known.
Earthquakes
The West Napa Fault is a likely source for the magnitude 6.0 South Napa earthquake that hit Napa County on August 24, 2014. Seismologists were not able to determine the exact fault on which the quake occurred, because faults are usually identified by their expression on the surface.
The epicenter for the 2000 Yountville earthquake which occurred on September 3, 2000, is also near the West Napa Fault.
See also
Green Valley Fault – northern extension of the East Bay Concord Fault.
This brief starts where responsible research should: with the source description of “West Napa Fault” as open-knowledge reference entry. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the general reference register because the source frames it as open-knowledge reference entry. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Nov 13, 2024. The linked authority identifier is Q18378800. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1976, 2023, 2014 and 2000.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. 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 “West Napa Fault”, its source revision and the description used here.
- Expand the search: follow West Napa Fault primary sources, West Napa Fault archive and West 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 “West Napa Fault”?
- 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 “West Napa Fault” 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.