Earthquake · reviewed by a seismologist
M 1.9md
Earthquake near Yountville, CA
No earthquake was likely felt in Yountville in the 24 hours to 10:39 am PST (18:39 UTC). The last one was M 2.4, 19 km (12 mi) SSE, at 10:47 am PDT on 6 October 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Yountville
This page: a magnitude 1.9 earthquake was recorded 18 km (11 mi) northeast of Yountville, CA, at 12:55 pm PDT on 27 July 2023 (19:55 UTC), 7.9 km deep.
USGS: 18 km NE of Yountville, CA
83 km (52 mi) NNE of San Francisco, CA · 25 km (15 mi) NNE of Napa, CA
- When
- 12:55 pm PDT on 27 July 2023 ()
- Where
- 18 km (11 mi) northeast of Yountville, CA · earthquakes near Yountville
- Magnitude
- M 1.9 (md)
- Depth
- 7.9 km below the surface
- Felt
- no reports yet
- Nearest
- Napa County, 11 km W
- Nearest mapped fault
- Hunting Creek-Berryessa fault system, 5 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1204 days ago
Earthquake alerts for Yountville, CA
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth, people at rest would likely notice it out to about 12 km (7 mi) from the epicentre. In Yountville, 18 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.
Earthquakes near other towns within 30 km: Winters, Allendale, Angwin, Hartley, Saint Helena, Deer Park.
How big was it?
This earthquake released about 19 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 810,000× the energy of this one
- Magna, Utah 2020 M 5.7 580,000× the energy of this one
- Around the size people start to feel M 3.0 51× the energy of this one
- This earthquake M 1.9 about 19 lb of TNT
Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.
For this area
The largest earthquake within 50 km since 2016 was M 4.4 on 2022-09-14 — about 6,200 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 6.0 The 2014 South Napa, California Earthquake · 34 km SSW of this epicentre
- 5.4 South of Elmira, California · 34 km SE of this epicentre
Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.
Where
Epicentre 38.5035, -122.1948. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Napa County, CA | 11 km (7 mi) | W | earthquakes near Napa County |
| Yolo County, CA | 32 km (20 mi) | NE | earthquakes near Yolo County |
| Solano County, CA | 34 km (21 mi) | SE | earthquakes near Solano County |
| Sonoma County, CA | 64 km (40 mi) | W | earthquakes near Sonoma County |
| Contra Costa County, CA | 68 km (42 mi) | SSE | earthquakes near Contra Costa County |
| Marin County, CA | 70 km (43 mi) | SW | earthquakes near Marin County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
44 earthquakes have been recorded within 50 km since this one.
- 2.1 13 km SE of Middletown, CA
- 2.7 12 km SE of Middletown, CA
- 2.0 12 km SE of Middletown, CA
- 2.8 12 km SE of Middletown, CA
- 1.5 12 km SE of Middletown, CA
- 1.7 12 km SE of Middletown, CA
- 1.7 12 km SE of Middletown, CA
- 1.8 13 km SE of Middletown, CA
- 1.7 13 km SE of Middletown, CA
- 2.2 12 km SE of Middletown, CA
- 2.5 12 km SE of Middletown, CA
- 2.1 12 km SE of Middletown, CA
- 1.5 12 km SE of Middletown, CA
- 1.5 12 km SE of Middletown, CA
- 2.4 12 km SE of Middletown, CA
Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.
On USGS
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.