QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Santa Rosa, CA

No earthquake was likely felt in Santa Rosa in the 24 hours to 1:34 pm PST (21:34 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 2.4 earthquake was recorded 32 km (20 mi) north-northwest of Santa Rosa, CA, at 12:41 am PDT on 23 October 2017 (07:41 UTC), 4.8 km deep. 5 people have reported feeling it to USGS.

USGS: 6 km E of Geyserville, California

32 km (20 mi) NNW of Santa Rosa, CA · 110 km (68 mi) NNW of San Francisco, CA

12:41 am PDT, Oct 23, 2017 · · 4.8 km deep · released about 120 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 44 kmNapa County 49 kmColusa County 72 kmMarin County 74 kmYolo County 80 kmSolano County 92 kmMendocino County 96 kmSutter County 103 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
12:41 am PDT on 23 October 2017 ()
Where
32 km (20 mi) north-northwest of Santa Rosa, CA · earthquakes near Santa Rosa
Magnitude
M 2.4 (md)
Depth
4.8 km below the surface
Felt
5 reports · strongest reported intensity III
Nearest
Sonoma County, 23 km SSW
Nearest mapped fault
Maacama fault, under 1 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 3307 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 20 km (12 mi) from the epicentre. In Santa Rosa, 32 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 12 km, intensity II · Cobb 15 km, intensity II · Windsor 19 km, intensity II · Cloverdale 20 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 92,000× the energy of this one
  3. Around the size people start to feel M 3.0 8.2× the energy of this one
  4. This earthquake M 2.4 about 120 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 8,500 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 · 44 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 38.7148, -122.8247. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 23 km (14 mi) SSW earthquakes near Sonoma County
Lake County, CA 44 km (27 mi) N earthquakes near Lake County
Napa County, CA 49 km (31 mi) ESE earthquakes near Napa County
Colusa County, CA 72 km (45 mi) NE earthquakes near Colusa County
Marin County, CA 74 km (46 mi) S earthquakes near Marin County
Yolo County, CA 80 km (50 mi) E earthquakes near Yolo County

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

Aftershocks so far

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

  1. 1.9 6 km W of Cobb, California
  2. 1.6 7 km E of Clearlake Oaks, California
  3. 1.5 7 km S of Cobb, California
  4. 1.9 8 km W of Cobb, California
  5. 1.7 5 km SSW of Cobb, California
  6. 1.6 6 km W of Cobb, California
  7. 1.8 7 km W of Cobb, California
  8. 1.9 7 km W of Cobb, California
  9. 1.5 7 km S of Cobb, California
  10. 1.9 8 km W of Cobb, California
  11. 2.1 4 km W of Cobb, California
  12. 1.6 7 km W of Cobb, California
  13. 1.6 7 km W of Cobb, California
  14. 2.8 7 km WSW of Cobb, California
  15. 1.6 5 km S 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.