QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near Santa Rosa, CA

No earthquake was likely felt in Santa Rosa in the 24 hours to 11:45 pm PST (07:45 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 2.1 earthquake was recorded 31 km (19 mi) north-northwest of Santa Rosa, CA, at 6:22 am PDT on 19 September 2017 (13:22 UTC), 3.9 km deep. 1 person has reported feeling it to USGS.

USGS: 8 km E of Geyserville, California

30 km (19 mi) NNW of Santa Rosa, CA · 109 km (68 mi) NNW of San Francisco, CA

6:22 am PDT, Sep 19, 2017 · · 3.9 km deep · released about 43 lb of TNT

Every earthquake near Santa Rosa Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sonoma County 23 kmLake County 45 kmNapa County 47 kmColusa County 71 kmMarin County 73 kmYolo County 78 kmSolano County 90 kmMendocino County 98 kmSutter County 102 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
6:22 am PDT on 19 September 2017 ()
Where
31 km (19 mi) north-northwest of Santa Rosa, CA · earthquakes near Santa Rosa
Magnitude
M 2.1 (md)
Depth
3.9 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Sonoma County, 23 km SSW
Nearest mapped fault
Maacama 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 1558 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, 31 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: Healdsburg 13 km, intensity II · Cobb 14 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 43 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 5.8 350,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 43 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 23,000 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 · 44 km S of this epicentre
  2. 5.3 Northern California · 43 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 38.7097, -122.8013. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 23 km (14 mi) SSW earthquakes near Sonoma County
Lake County, CA 45 km (28 mi) N earthquakes near Lake County
Napa County, CA 47 km (29 mi) ESE earthquakes near Napa County
Colusa County, CA 71 km (44 mi) NE earthquakes near Colusa County
Marin County, CA 73 km (46 mi) S earthquakes near Marin County
Yolo County, CA 78 km (49 mi) E earthquakes near Yolo 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. 1.6 8 km WSW of Cobb, California
  2. 2.5 8 km WSW of Cobb, California
  3. 1.6 6 km W of Cobb, California
  4. 1.9 8 km WSW of Cobb, California
  5. 1.5 3 km WSW of Cobb, California
  6. 1.5 3 km W of Cobb, California
  7. 2.9 6 km W of Kenwood, California
  8. 1.5 Northern California
  9. 1.5 7 km W of Cobb, California
  10. 1.5 2 km W of Cobb, California
  11. 1.5 5 km SSW of Cobb, California
  12. 1.9 8 km ENE of Hidden Valley Lake, California
  13. 1.5 8 km W of Cobb, California
  14. 1.9 8 km W of Cobb, California
  15. 1.8 8 km W of Cobb, California

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.