QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Santa Rosa, CA

No earthquake was likely felt in Santa Rosa in the 24 hours to 3:00 am PST (11:00 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 1.9 earthquake was recorded 7 km (5 mi) southeast of Santa Rosa, CA, at 10:36 pm PDT on 20 July 2021 (05:36 UTC), 9.4 km deep.

USGS: 7km ESE of Roseland, CA

7 km (5 mi) SE of Santa Rosa, CA

10:36 pm PDT, Jul 20, 2021 · · 9.4 km deep · released about 21 lb of TNT

Every earthquake near Santa Rosa Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sonoma County 28 kmNapa County 31 kmMarin County 39 kmSolano County 64 kmYolo County 72 kmLake County 80 kmContra Costa County 81 kmSan Francisco County 81 kmColusa 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
10:36 pm PDT on 20 July 2021 ()
Where
7 km (5 mi) southeast of Santa Rosa, CA · earthquakes near Santa Rosa
Magnitude
M 1.9 (md)
Depth
9.4 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 28 km WNW
Nearest mapped fault
Bennett Valley fault, 3 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 1932 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 11 km (7 mi) from the epicentre. In Santa Rosa, 7 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: Rohnert Park 7 km, intensity II · Santa Rosa 7 km, intensity II · Kenwood 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 21 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 5.8 730,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 520,000× the energy of this one
  3. Around the size people start to feel M 3.0 46× the energy of this one
  4. This earthquake M 1.9 about 21 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 4.2 on 2018-01-18 — about 3,100 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 · 36 km SE of this epicentre
  2. 5.3 3 km E of Bloomfield, California · 16 km WSW of this epicentre
  3. 5.3 Northern California · 17 km WSW 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 38.3942, -122.6522. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 28 km (17 mi) WNW earthquakes near Sonoma County
Napa County, CA 31 km (19 mi) ENE earthquakes near Napa County
Marin County, CA 39 km (24 mi) SSW earthquakes near Marin County
Solano County, CA 64 km (40 mi) ESE earthquakes near Solano County
Yolo County, CA 72 km (45 mi) ENE earthquakes near Yolo County
Lake County, CA 80 km (50 mi) N earthquakes near Lake County

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

Aftershocks so far

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

  1. 2.1 2km SSW of Bodega Bay, CA
  2. 1.8 2km SSW of Bodega Bay, CA
  3. 1.8 2km SSW of Bodega Bay, CA
  4. 1.6 2km NNE of The Geysers, CA
  5. 1.7 5km NW of The Geysers, CA
  6. 2.5 12km ESE of Angwin, CA
  7. 1.5 13km E of Angwin, CA
  8. 2.4 13km NE of Yountville, CA
  9. 1.5 8km SW of Calistoga, CA
  10. 1.6 6km NW of The Geysers, CA
  11. 2.3 2km WNW of Tomales, CA
  12. 1.6 12km ESE of Hidden Valley Lake, CA
  13. 1.7 3km E of The Geysers, CA
  14. 1.8 4km NNW of The Geysers, CA
  15. 1.8 10km NE of Napa, 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.