QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Napa, CA

No earthquake was likely felt in Napa in the 24 hours to 6:26 am PST (14:26 UTC). The last one was M 2.4, 6 km (3 mi) SE, at 10:47 am PDT on 6 October 2026, estimated intensity III (weak) in town; 1 felt report to USGS. Every earthquake near Napa

This page: a magnitude 1.7 earthquake was recorded 10 km (6 mi) northeast of Napa, CA, at 2:44 pm PST on 15 November 2021 (22:44 UTC), 6.7 km deep.

USGS: 10km NE of Napa, CA

11 km (7 mi) NE of Napa, CA · 68 km (42 mi) NNE of San Francisco, CA

2:44 pm PST, Nov 15, 2021 · · 6.7 km deep · released about 9.6 lb of TNT

10 km30 km60 km120 km N Napa County 19 kmSolano County 25 kmYolo County 44 kmContra Costa County 54 kmMarin County 59 kmSonoma County 66 kmSacramento County 75 kmAlameda County 83 kmSutter County 86 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
2:44 pm PST on 15 November 2021 ()
Where
10 km (6 mi) northeast of Napa, CA · earthquakes near Napa
Magnitude
M 1.7 (md)
Depth
6.7 km below the surface
Felt
no reports yet
Nearest
Napa County, 19 km NW
Nearest mapped fault
Green Valley fault, under 1 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 1816 days ago

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 10 km (6 mi) from the epicentre. In Napa, 10 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: Green Valley, Yountville, Vacaville, Fairfield, Suisun, American Canyon.

How big was it?

This earthquake released about 9.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 99× the energy of this one
  4. This earthquake M 1.7 about 9.6 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 4.5 on 2019-10-15 — about 15,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 6.0 The 2014 South Napa, California Earthquake · 19 km SSW of this epicentre
  2. 5.4 South of Elmira, California · 27 km ESE 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 38.3622, -122.2002. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Napa County, CA 19 km (12 mi) NW earthquakes near Napa County
Solano County, CA 25 km (16 mi) ESE earthquakes near Solano County
Yolo County, CA 44 km (27 mi) NE earthquakes near Yolo County
Contra Costa County, CA 54 km (33 mi) SSE earthquakes near Contra Costa County
Marin County, CA 59 km (37 mi) SW earthquakes near Marin County
Sonoma County, CA 66 km (41 mi) WNW earthquakes near Sonoma County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

22 earthquakes have been recorded within 50 km since this one.

  1. 1.8 5km NW of Pittsburg, CA
  2. 1.8 5km E of Vallejo, CA
  3. 1.9 3km WSW of American Canyon, CA
  4. 1.5 2km NNW of Green Valley, CA
  5. 1.6 4km N of Lafayette, CA
  6. 1.6 5km N of Lafayette, CA
  7. 1.7 12km NNE of Angwin, CA
  8. 1.7 5km WSW of Pacheco, CA
  9. 2.0 5km W of Yountville, CA
  10. 2.1 6km ENE of Kenwood, CA
  11. 1.6 5km NE of Larkfield-Wikiup, CA
  12. 1.5 6km W of Kenwood, CA
  13. 1.7 5km NE of Larkfield-Wikiup, CA
  14. 1.6 6km E of Vallejo, CA
  15. 1.9 6km E of Vallejo, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.