QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Napa, CA

No earthquake was likely felt in Napa in the 24 hours to 4:31 am PST (12:31 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 1.9 earthquake was recorded 9 km (6 mi) north-northeast of Napa, CA, at 10:57 pm PST on 16 December 2019 (06:57 UTC), 3.0 km deep. 2 people have reported feeling it to USGS.

USGS: 9km NNE of Napa, CA

10 km (6 mi) NE of Napa, CA · 68 km (42 mi) NNE of San Francisco, CA

10:57 pm PST, Dec 16, 2019 · · 3.0 km deep · released about 19 lb of TNT

10 km30 km60 km120 km N Napa County 17 kmSolano County 28 kmYolo County 45 kmContra Costa County 56 kmMarin County 57 kmSonoma County 63 kmSacramento County 78 kmAlameda County 85 kmSutter County 87 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
10:57 pm PST on 16 December 2019 ()
Where
9 km (6 mi) north-northeast of Napa, CA · earthquakes near Napa
Magnitude
M 1.9 (md)
Depth
3.0 km below the surface
Felt
2 reports · strongest reported intensity III
Nearest
Napa County, 17 km NNW
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 2511 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 14 km (9 mi) from the epicentre. In Napa, 9 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.

Likely felt in: Napa 9 km, intensity II. Estimated for each town centre; each link is that town's own record.

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.

  1. Mineral, Virginia 2011 M 5.8 790,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 560,000× the energy of this one
  3. Around the size people start to feel M 3.0 50× the energy of this one
  4. 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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

  1. 6.0 The 2014 South Napa, California Earthquake · 18 km SSW of this epicentre
  2. 5.4 South of Elmira, California · 30 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 38.3692, -122.2328. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Napa County, CA 17 km (11 mi) NNW earthquakes near Napa County
Solano County, CA 28 km (17 mi) ESE earthquakes near Solano County
Yolo County, CA 45 km (28 mi) NE earthquakes near Yolo County
Contra Costa County, CA 56 km (35 mi) SSE earthquakes near Contra Costa County
Marin County, CA 57 km (35 mi) SW earthquakes near Marin County
Sonoma County, CA 63 km (39 mi) WNW earthquakes near Sonoma County

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

Aftershocks so far

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

  1. 1.5 6km ENE of Vallejo, CA
  2. 1.8 14km E of Angwin, CA
  3. 1.6 15km E of Angwin, CA
  4. 2.1 10km ESE of Hidden Valley Lake, CA
  5. 2.1 6km WSW of Glen Ellen, CA
  6. 1.5 5km E of Vallejo, CA
  7. 1.6 14km ESE of Hidden Valley Lake, CA
  8. 2.5 12km ESE of Angwin, CA
  9. 1.9 4km SSE of Elmira, CA
  10. 1.8 5km NNW of Green Valley, CA
  11. 1.6 5km NE of Kenwood, CA
  12. 2.3 16km SE of Hidden Valley Lake, CA
  13. 1.7 14km E of Angwin, CA
  14. 2.6 0km S of East Richmond Heights, CA
  15. 2.4 2km E of Pacheco, 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.