QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2md

Earthquake near Santa Rosa, CA

No earthquake was likely felt in Santa Rosa in the 24 hours to 11:43 am PST (19:43 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 2.2 earthquake was recorded 42 km (26 mi) west-northwest of Santa Rosa, CA, at 6:32 am PDT on 22 May 2018 (13:32 UTC), 7.7 km deep.

USGS: 18km NE of Fort Ross, CA

42 km (26 mi) WNW of Santa Rosa, CA · 114 km (71 mi) NNW of San Francisco, CA

6:32 am PDT, May 22, 2018 · · 7.7 km deep · released about 60 lb of TNT

10 km30 km60 km120 km N Sonoma County 21 kmLake County 61 kmNapa County 70 kmMarin County 73 kmMendocino County 92 kmColusa County 96 kmSan Francisco County 102 kmYolo County 105 kmSolano County 111 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
6:32 am PDT on 22 May 2018 ()
Where
42 km (26 mi) west-northwest of Santa Rosa, CA · earthquakes near Santa Rosa
Magnitude
M 2.2 (md)
Depth
7.7 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 21 km SE
Nearest mapped fault
Alexander-Redwood Hill fault, 17 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 3096 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 17 km (11 mi) from the epicentre. In Santa Rosa, 42 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.

Earthquakes near other towns within 30 km: Guerneville, Cloverdale, Healdsburg, Monte Rio, Forestville, Camp Meeker.

How big was it?

This earthquake released about 60 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 250,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 180,000× the energy of this one
  3. Around the size people start to feel M 3.0 16× the energy of this one
  4. This earthquake M 2.2 about 60 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 5.0 on 2016-12-14 — about 16,000 times the energy of this one.

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

  1. 5.3 3 km E of Bloomfield, California · 46 km SE of this epicentre
  2. 5.3 Northern California · 44 km SE 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 38.6448, -123.1170. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 21 km (13 mi) SE earthquakes near Sonoma County
Lake County, CA 61 km (38 mi) NNE earthquakes near Lake County
Napa County, CA 70 km (44 mi) ESE earthquakes near Napa County
Marin County, CA 73 km (46 mi) SSE earthquakes near Marin County
Mendocino County, CA 92 km (57 mi) NNW earthquakes near Mendocino County
Colusa County, CA 96 km (60 mi) NE earthquakes near Colusa County

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

Aftershocks so far

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

  1. 3.0 2km W of Anderson Springs, CA
  2. 1.8 2km W of Anderson Springs, CA
  3. 1.8 4km NNW of The Geysers, CA
  4. 1.9 4km NW of The Geysers, CA
  5. 2.7 4km NNW of The Geysers, CA
  6. 2.9 4km NNW of The Geysers, CA
  7. 1.6 13km WSW of Lakeport, CA
  8. 1.5 3km ENE of The Geysers, CA
  9. 1.7 6km NW of The Geysers, CA
  10. 1.6 13km ENE of Cloverdale, CA
  11. 1.5 6km WNW of The Geysers, CA
  12. 1.6 3km SE of The Geysers, CA
  13. 1.7 6km NW of The Geysers, CA
  14. 1.7 15km SE of Boonville, CA
  15. 1.7 10km 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.