QuakeIndex

Earthquake · automatic estimate, may change

M 2.1md

Earthquake near Santa Rosa, CA

Yes. A magnitude 2.1 earthquake was recorded 35 km (22 mi) north of Santa Rosa, CA, at 12:36 am PDT on 21 October 2026 (07:36 UTC), 2.2 km deep. No felt reports to USGS yet. The magnitude and location are an automatic first estimate and may change.

USGS: 3 km SW of Anderson Springs, CA

34 km (21 mi) N of Santa Rosa, CA · 111 km (69 mi) NNW of San Francisco, CA

12:36 am PDT, Oct 21, 2026 · · 2.2 km deep · released about 38 lb of TNT

10 km30 km60 km120 km N Sonoma County 31 kmLake County 39 kmNapa County 44 kmColusa County 63 kmYolo County 71 kmMarin County 78 kmSolano County 87 kmSutter County 93 kmMendocino County 98 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
12:36 am PDT on 21 October 2026 ()
Where
35 km (22 mi) north of Santa Rosa, CA · earthquakes near Santa Rosa
Magnitude
M 2.1 (md)
Depth
2.2 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 31 km SW
Nearest mapped fault
Maacama fault, 11 km from its surface trace — near is not the same as on
Status
Automatic — a machine’s first estimate, which may change

USGS · last changed by USGS · we first saw it 15 hours 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, 35 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: Cobb 8 km, intensity II · Middletown 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 38 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 390,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 280,000× the energy of this one
  3. Around the size people start to feel M 3.0 25× the energy of this one
  4. This earthquake M 2.1 about 38 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 26,000 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 · 49 km S of this epicentre
  2. 5.3 Northern California · 49 km S 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 38.7537, -122.7177. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 31 km (19 mi) SW earthquakes near Sonoma County
Lake County, CA 39 km (25 mi) N earthquakes near Lake County
Napa County, CA 44 km (27 mi) SE earthquakes near Napa County
Colusa County, CA 63 km (39 mi) NE earthquakes near Colusa County
Yolo County, CA 71 km (44 mi) E earthquakes near Yolo County
Marin County, CA 78 km (49 mi) S earthquakes near Marin County

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

Aftershocks so far

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

  1. 0.7 6 km WNW of Cobb, CA
  2. 0.8 7 km NW of The Geysers, CA
  3. 0.8 5 km WNW of Cobb, CA
  4. 1.1 9 km NW of The Geysers, CA
  5. 1.4 6 km WNW of Cobb, CA
  6. 1.0 4 km NW of The Geysers, CA
  7. 1.8 9 km NW of The Geysers, CA
  8. 0.3 9 km NW of The Geysers, CA
  9. 1.0 6 km WNW of Cobb, CA
  10. 0.7 4 km W of Cobb, CA
  11. 0.7 7 km WNW of Cobb, CA
  12. 1.5 6 km 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.