QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Santa Rosa, CA

No earthquake was likely felt in Santa Rosa in the 24 hours to 5:51 am PST (13:51 UTC). The last one was M 1.9, 5 km (3 mi) NE, at 2:01 pm PDT on 23 October 2026, estimated intensity II (weak) in town. Every earthquake near Santa Rosa

This page: a magnitude 2.4 earthquake was recorded 15 km (10 mi) southeast of Santa Rosa, CA, at 8:35 am PDT on 15 September 2023 (15:35 UTC), 10 km deep. 5 people have reported feeling it to USGS.

USGS: 4 km W of Glen Ellen, CA

14 km (9 mi) NNE of Petaluma, CA · 66 km (41 mi) NNW of San Francisco, CA

8:35 am PDT, Sep 15, 2023 · · 10 km deep · released about 120 lb of TNT

Every earthquake near Santa Rosa Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Napa County 27 kmSonoma County 36 kmMarin County 37 kmSolano County 56 kmYolo County 68 kmContra Costa County 73 kmSan Francisco County 81 kmLake County 85 kmColusa County 96 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
8:35 am PDT on 15 September 2023 ()
Where
15 km (10 mi) southeast of Santa Rosa, CA · earthquakes near Santa Rosa
Magnitude
M 2.4 (md)
Depth
10 km below the surface
Felt
5 reports · strongest reported intensity II
Nearest
Napa County, 27 km NE
Nearest mapped fault
Bennett 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 1150 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 18 km (11 mi) from the epicentre. In Santa Rosa, 15 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: Kenwood 7 km, intensity II · Agua Caliente 8 km, intensity II · Rohnert Park 11 km, intensity II · Petaluma 15 km, intensity II · Santa Rosa 15 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 120,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 86,000× the energy of this one
  3. Around the size people start to feel M 3.0 7.7× the energy of this one
  4. This earthquake M 2.4 about 120 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 930 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 6.0 The 2014 South Napa, California Earthquake · 28 km SE of this epicentre
  2. 5.3 3 km E of Bloomfield, California · 21 km WSW of this epicentre
  3. 5.3 Northern California · 23 km W 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 38.3587, -122.5720. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Napa County, CA 27 km (17 mi) NE earthquakes near Napa County
Sonoma County, CA 36 km (22 mi) WNW earthquakes near Sonoma County
Marin County, CA 37 km (23 mi) SSW earthquakes near Marin County
Solano County, CA 56 km (35 mi) E earthquakes near Solano County
Yolo County, CA 68 km (42 mi) ENE earthquakes near Yolo County
Contra Costa County, CA 73 km (45 mi) SE earthquakes near Contra Costa County

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

Aftershocks so far

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

  1. 1.6 6 km ESE of Santa Venetia, CA
  2. 1.5 12 km SE of Middletown, CA
  3. 1.9 2 km NE of The Geysers, CA
  4. 1.9 12 km SE of Middletown, CA
  5. 1.6 12 km SE of Middletown, CA
  6. 1.8 3 km ENE of The Geysers, CA
  7. 1.5 12 km SE of Middletown, CA
  8. 2.1 13 km SE of Middletown, CA
  9. 2.7 12 km SE of Middletown, CA
  10. 2.0 12 km SE of Middletown, CA
  11. 2.8 12 km SE of Middletown, CA
  12. 1.5 12 km SE of Middletown, CA
  13. 1.7 12 km SE of Middletown, CA
  14. 1.7 12 km SE of Middletown, CA
  15. 2.8 3 km ESE of The Geysers, 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.