Earthquake · reviewed by a seismologist
M 2.8md
Earthquake near Yountville, CA
No earthquake was likely felt in Yountville in the 24 hours to 7:19 pm PST (03:19 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 2.8 earthquake was recorded 10 km (6 mi) east-northeast of Yountville, CA, at 2:15 pm PDT on 23 March 2021 (21:15 UTC), 11 km deep. 42 people have reported feeling it to USGS.
USGS: 10km ENE of Yountville, CA
15 km (9 mi) NNE of Napa, CA · 73 km (46 mi) N of San Francisco, CA
- When
- 2:15 pm PDT on 23 March 2021 ()
- Where
- 10 km (6 mi) east-northeast of Yountville, CA · earthquakes near Yountville
- Magnitude
- M 2.8 (md)
- Depth
- 11 km below the surface
- Felt
- 42 reports · strongest reported intensity III
- Nearest
- Napa County, 11 km NW
- Nearest mapped fault
- Green Valley fault, 2 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 1990 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 small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 26 km (16 mi) from the epicentre. In Yountville, 10 km away, the estimate is intensity III (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.
Likely felt in: Napa 15 km, intensity II · Agua Caliente 23 km, intensity II · Angwin 24 km, intensity II · Vacaville 25 km, intensity II · Kenwood 25 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 490 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 31,000× the energy of this one
- Magna, Utah 2020 M 5.7 22,000× the energy of this one
- Around the size people start to feel M 3.0 1.9× the energy of this one
- This earthquake M 2.8 about 490 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 6.0 The 2014 South Napa, California Earthquake · 24 km SSW of this epicentre
- 5.4 South of Elmira, California · 34 km ESE of this epicentre
- 5.3 3 km E of Bloomfield, California · 50 km WSW 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 38.4262, -122.2557. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Napa County, CA | 11 km (7 mi) | NW | earthquakes near Napa County |
| Solano County, CA | 33 km (20 mi) | ESE | earthquakes near Solano County |
| Yolo County, CA | 42 km (26 mi) | NE | earthquakes near Yolo County |
| Sonoma County, CA | 59 km (37 mi) | W | earthquakes near Sonoma County |
| Marin County, CA | 60 km (37 mi) | SW | earthquakes near Marin County |
| Contra Costa County, CA | 62 km (39 mi) | SSE | earthquakes near Contra Costa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
10 earthquakes have been recorded within 50 km since this one.
- 1.6 4km W of Kenwood, CA
- 1.9 10km SSE of Elmira, CA
- 1.6 6km SSW of Calistoga, CA
- 1.6 21km ENE of Hidden Valley Lake, CA
- 1.6 3km NNW of Angwin, CA
- 1.6 6km SSW of Calistoga, CA
- 3.3 6km S of Calistoga, CA
- 2.5 6km S of Calistoga, CA
- 1.6 10km WNW of Calistoga, CA
- 1.8 11km ENE of Yountville, 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.