QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Bolinas, CA

No earthquake was likely felt in Bolinas in the 24 hours to 11:01 pm PST (07:01 UTC). The last one was M 3.8, 50 km (31 mi) ESE, at 8:30 am PDT on 13 August 2026, estimated intensity II (weak) in town; 7,876 felt reports to USGS. Every earthquake near Bolinas

This page: a magnitude 2.4 earthquake was recorded 11 km (7 mi) south-southwest of Bolinas, CA, at 4:28 pm PST on 9 February 2026 (00:28 UTC), 10.0 km deep. 5 people have reported feeling it to USGS.

USGS: 11 km SSW of Bolinas, CA

27 km (17 mi) W of San Francisco, CA · 26 km (16 mi) WNW of Daly City, CA

4:28 pm PST, Feb 9, 2026 · · 10.0 km deep · released about 100 lb of TNT

10 km30 km60 km120 km N Marin County 26 kmSan Francisco County 29 kmSan Mateo County 54 kmContra Costa County 69 kmAlameda County 74 kmSonoma County 81 kmNapa County 84 kmSolano County 85 kmSanta Cruz County 110 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
4:28 pm PST on 9 February 2026 ()
Where
11 km (7 mi) south-southwest of Bolinas, CA · earthquakes near Bolinas
Magnitude
M 2.4 (md)
Depth
10.0 km below the surface
Felt
5 reports · strongest reported intensity II
Nearest
Marin County, 26 km N
Nearest mapped fault
San Gregorio 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 195 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 18 km (11 mi) from the epicentre. In Bolinas, 11 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: Tamalpais Valley, Tamalpais-Homestead Valley, Mill Valley, Marin City, Strawberry, Kentfield.

How big was it?

This earthquake released about 100 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 5.8 150,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 110,000× the energy of this one
  3. Around the size people start to feel M 3.0 9.4× the energy of this one
  4. This earthquake M 2.4 about 100 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 4.4 on 2018-01-04 — about 1,100 times the energy of this one.

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

  1. 7.9 The 1906 San Francisco, California Earthquake · 17 km ESE of this epicentre
  2. 5.3 The 1957 San Francisco, California Earthquake · 27 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 37.8165, -122.7253. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Marin County, CA 26 km (16 mi) N earthquakes near Marin County
San Francisco County, CA 29 km (18 mi) WSW earthquakes near San Francisco County
San Mateo County, CA 54 km (34 mi) SE earthquakes near San Mateo County
Contra Costa County, CA 69 km (43 mi) E earthquakes near Contra Costa County
Alameda County, CA 74 km (46 mi) ESE earthquakes near Alameda County
Sonoma County, CA 81 km (50 mi) NNW earthquakes near Sonoma County

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

Aftershocks so far

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

  1. 1.6 3 km NE of Millbrae, CA
  2. 1.6 2 km SSE of Pacifica, CA
  3. 2.3 2 km SE of Pacifica, CA
  4. 1.5 3 km E of Alameda, CA
  5. 1.9 2 km SE of Pacifica, CA
  6. 1.6 2 km SE of Pacifica, CA
  7. 1.7 2 km ESE of Pacifica, CA
  8. 1.6 2 km SE of East Richmond Heights, CA
  9. 1.6 3 km NW of Hercules, CA
  10. 1.7 3 km NW of Hercules, CA
  11. 1.7 2 km SSE of Pacifica, CA
  12. 2.7 2 km ESE of Pinole, CA
  13. 1.8 2 km SE of Pacifica, CA
  14. 1.9 3 km ESE of Berkeley, CA
  15. 1.9 1 km ESE of Pinole, 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.