QuakeIndex

Earthquake · reviewed by a seismologist

M 3.2ml

Earthquake near Santa Rosa, CA

No earthquake was likely felt in Santa Rosa in the 24 hours to 3:30 am PST (11:30 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 3.2 earthquake was recorded 4 km (2 mi) east of Santa Rosa, CA, at 5:45 am PDT on 30 September 2021 (12:45 UTC), 9.3 km deep. 1,048 people have reported feeling it to USGS.

USGS: 3km ESE of Santa Rosa, CA

in Santa Rosa, CA

5:45 am PDT, Sep 30, 2021 · · 9.3 km deep · released about 1.1 tons of TNT

Every earthquake near Santa Rosa Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sonoma County 24 kmNapa County 31 kmMarin County 44 kmSolano County 67 kmYolo County 72 kmLake County 74 kmSan Francisco County 85 kmContra Costa County 86 kmColusa County 90 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
5:45 am PDT on 30 September 2021 ()
Where
4 km (2 mi) east of Santa Rosa, CA · earthquakes near Santa Rosa
Magnitude
M 3.2 (ml)
Depth
9.3 km below the surface
Felt
1,048 reports · strongest reported intensity IV
Nearest
Sonoma County, 24 km WNW
Nearest mapped fault
Rodgers Creek 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 1520 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 47 km (29 mi) from the epicentre. In Santa Rosa, 4 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: Santa Rosa 4 km, intensity III · Kenwood 11 km, intensity III · Rohnert Park 12 km, intensity III · Calistoga 17 km, intensity III · Windsor 17 km, intensity III · Agua Caliente 21 km, intensity II · Petaluma 23 km, intensity II · Angwin 24 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 160,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7,200× the energy of this one
  3. Magna, Utah 2020 M 5.7 5,100× the energy of this one
  4. This earthquake M 3.2 about 1.1 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.2× more

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 5.0 on 2016-12-14 — about 470 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 · 40 km SE of this epicentre
  2. 5.3 3 km E of Bloomfield, California · 18 km SW of this epicentre
  3. 5.3 Northern California · 19 km SW 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 38.4417, -122.6712. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 24 km (15 mi) WNW earthquakes near Sonoma County
Napa County, CA 31 km (19 mi) ENE earthquakes near Napa County
Marin County, CA 44 km (27 mi) S earthquakes near Marin County
Solano County, CA 67 km (41 mi) ESE earthquakes near Solano County
Yolo County, CA 72 km (45 mi) ENE earthquakes near Yolo County
Lake County, CA 74 km (46 mi) N earthquakes near Lake County

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

Aftershocks so far

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

  1. 1.7 5km W of Cobb, CA
  2. 1.9 6km WNW of The Geysers, CA
  3. 1.9 6km WNW of The Geysers, CA
  4. 1.6 1km NNE of The Geysers, CA
  5. 2.7 5km WNW of The Geysers, CA
  6. 1.9 3km N of The Geysers, CA
  7. 1.5 3km N of The Geysers, CA
  8. 3.1 1km NNW of The Geysers, CA
  9. 1.6 1km NNW of The Geysers, CA
  10. 1.7 8km W of Cobb, CA
  11. 1.5 2km NNW of The Geysers, CA
  12. 2.0 3km WNW of Cobb, CA
  13. 1.8 15km ESE of Hidden Valley Lake, CA
  14. 2.4 4km NW of The Geysers, CA
  15. 1.6 7km WNW of Cobb, 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.