QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

Earthquake near Temelec, CA

No earthquake was likely felt in Temelec in the 24 hours to 3:56 am PST (11:56 UTC). The last one was M 2.4, 21 km (13 mi) E, at 10:47 am PDT on 6 October 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Temelec

This page: a magnitude 2.8 earthquake was recorded 6 km (4 mi) west of Temelec, CA, at 8:37 am PST on 24 December 2017 (16:37 UTC), 1.0 km deep. 65 people have reported feeling it to USGS.

USGS: 6km W of Temelec, CA

6 km (4 mi) ENE of Petaluma, CA · 56 km (35 mi) NNW of San Francisco, CA

8:37 am PST, Dec 24, 2017 · · 1.0 km deep · released about 450 lb of TNT

10 km30 km60 km120 km N Marin County 29 kmNapa County 34 kmSonoma County 42 kmSolano County 55 kmContra Costa County 66 kmSan Francisco County 73 kmYolo County 74 kmAlameda County 90 kmLake County 94 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
8:37 am PST on 24 December 2017 ()
Where
6 km (4 mi) west of Temelec, CA · earthquakes near Temelec
Magnitude
M 2.8 (md)
Depth
1.0 km below the surface
Felt
65 reports · strongest reported intensity III
Nearest
Marin County, 29 km SSW
Nearest mapped fault
Rodgers Creek 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 3214 days ago

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 Temelec, 6 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: Petaluma 7 km, intensity III · Agua Caliente 9 km, intensity III · Rohnert Park 14 km, intensity III · Kenwood 16 km, intensity II · Black Point-Green Point 18 km, intensity II · Novato 18 km, intensity II · Santa Rosa 23 km, intensity II · Napa 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 450 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.

  1. Mineral, Virginia 2011 M 5.8 34,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 24,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.1× the energy of this one
  4. This earthquake M 2.8 about 450 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:

  1. 6.0 The 2014 South Napa, California Earthquake · 23 km ESE of this epicentre
  2. 5.3 3 km E of Bloomfield, California · 22 km WNW of this epicentre
  3. 5.3 Northern California · 23 km WNW 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 38.2698, -122.5660. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Marin County, CA 29 km (18 mi) SSW earthquakes near Marin County
Napa County, CA 34 km (21 mi) NE earthquakes near Napa County
Sonoma County, CA 42 km (26 mi) NW earthquakes near Sonoma County
Solano County, CA 55 km (34 mi) E earthquakes near Solano County
Contra Costa County, CA 66 km (41 mi) SE earthquakes near Contra Costa County
San Francisco County, CA 73 km (45 mi) SW earthquakes near San Francisco 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.

  1. 1.9 10km ESE of Black Point-Green Point, CA
  2. 3.7 10km ESE of Black Point-Green Point, CA
  3. 2.3 3km NNW of Larkfield-Wikiup, CA
  4. 1.5 2km NNW of Larkfield-Wikiup, CA
  5. 2.5 3km NNW of Larkfield-Wikiup, CA
  6. 2.0 13km ESE of Angwin, CA
  7. 1.6 6km W of Yountville, CA
  8. 1.9 7km ENE of Angwin, CA
  9. 2.8 11km S of The Geysers, CA
  10. 1.8 4km NE of Angwin, CA
  11. 1.7 7km ENE of Penngrove, CA
  12. 2.0 6km NNE of Penngrove, CA
  13. 2.9 6km NNE of Penngrove, CA
  14. 2.4 6km NNE of Penngrove, CA
  15. 1.9 20km E of Angwin, 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.