QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

Earthquake near Santa Rosa, CA

No earthquake was likely felt in Santa Rosa in the 24 hours to 3:14 am PST (11:14 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 2.5 earthquake was recorded 5 km (3 mi) north of Santa Rosa, CA, at 1:04 pm PDT on 22 September 2018 (20:04 UTC), 6.8 km deep. 73 people have reported feeling it to USGS.

USGS: 4km N of Santa Rosa, CA

in Santa Rosa, CA

1:04 pm PDT, Sep 22, 2018 · · 6.8 km deep · released about 160 lb of TNT

10 km30 km60 km120 km N Sonoma County 19 kmNapa County 34 kmMarin County 48 kmLake County 69 kmSolano County 72 kmYolo County 73 kmColusa County 87 kmSan Francisco County 89 kmContra Costa County 91 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
1:04 pm PDT on 22 September 2018 ()
Where
5 km (3 mi) north of Santa Rosa, CA · earthquakes near Santa Rosa
Magnitude
M 2.5 (md)
Depth
6.8 km below the surface
Felt
73 reports · strongest reported intensity III
Nearest
Sonoma County, 19 km WNW
Nearest mapped fault
Rodgers Creek 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 2123 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 21 km (13 mi) from the epicentre. In Santa Rosa, 5 km away, the estimate is intensity III (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: Santa Rosa 5 km, intensity III · Windsor 11 km, intensity II · Calistoga 15 km, intensity II · Rohnert Park 16 km, intensity II · Kenwood 16 km, intensity II · Healdsburg 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 160 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 95,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 68,000× the energy of this one
  3. Around the size people start to feel M 3.0 6× the energy of this one
  4. This earthquake M 2.5 about 160 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 6,200 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 · 46 km SE of this epicentre
  2. 5.3 3 km E of Bloomfield, California · 21 km SSW of this epicentre
  3. 5.3 Northern California · 21 km SSW 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 38.4858, -122.7112. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 19 km (12 mi) WNW earthquakes near Sonoma County
Napa County, CA 34 km (21 mi) E earthquakes near Napa County
Marin County, CA 48 km (30 mi) S earthquakes near Marin County
Lake County, CA 69 km (43 mi) N earthquakes near Lake County
Solano County, CA 72 km (44 mi) ESE earthquakes near Solano County
Yolo County, CA 73 km (46 mi) ENE 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. 1.5 6km WNW of The Geysers, CA
  2. 1.5 1km NNE of The Geysers, CA
  3. 1.8 2km ESE of The Geysers, CA
  4. 1.6 6km W of Cobb, CA
  5. 1.5 6km WNW of Cobb, CA
  6. 1.8 7km NW of The Geysers, CA
  7. 1.6 7km NW of The Geysers, CA
  8. 1.8 7km NW of The Geysers, CA
  9. 1.7 2km W of Anderson Springs, CA
  10. 1.6 6km W of Cobb, CA
  11. 1.6 3km NE of The Geysers, CA
  12. 2.2 7km WNW of The Geysers, CA
  13. 1.6 7km NE of Rohnert Park, CA
  14. 1.7 7km NE of Rohnert Park, CA
  15. 2.0 3km SW of Anderson Springs, 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.