QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near San Francisco, CA

No earthquake was likely felt in San Francisco in the 24 hours to 5:26 am PST (13:26 UTC). The last one was M 2.6, 18 km (11 mi) ENE, at 6:23 pm PST on 1 November 2026, estimated intensity II (weak) in town; 114 felt reports to USGS. Every earthquake near San Francisco

This page: a magnitude 1.7 earthquake was recorded 16 km (10 mi) west of San Francisco, CA, at 1:26 am PDT on 12 June 2021 (08:26 UTC), 9.0 km deep.

USGS: 7km SSW of Muir Beach, CA

16 km (10 mi) W of San Francisco, CA

1:26 am PDT, Jun 12, 2021 · · 9.0 km deep · released about 9.3 lb of TNT

10 km30 km60 km120 km N Marin County 31 kmSan Francisco County 39 kmSan Mateo County 47 kmContra Costa County 58 kmAlameda County 63 kmSolano County 78 kmNapa County 82 kmSonoma County 86 kmSanta Cruz 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
1:26 am PDT on 12 June 2021 ()
Where
16 km (10 mi) west of San Francisco, CA · earthquakes near San Francisco
Magnitude
M 1.7 (md)
Depth
9.0 km below the surface
Felt
no reports yet
Nearest
Marin County, 31 km NNW
Nearest mapped fault
San Andreas 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 1977 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 8 km (5 mi) from the epicentre. In San Francisco, 16 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, Marin City, Sausalito, Mill Valley, Strawberry.

How big was it?

This earthquake released about 9.3 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 100× the energy of this one
  4. This earthquake M 1.7 about 9.3 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 12,000 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 · 7 km SE of this epicentre
  2. 5.3 The 1957 San Francisco, California Earthquake · 18 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 37.7985, -122.5987. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Marin County, CA 31 km (19 mi) NNW earthquakes near Marin County
San Francisco County, CA 39 km (24 mi) WSW earthquakes near San Francisco County
San Mateo County, CA 47 km (29 mi) SSE earthquakes near San Mateo County
Contra Costa County, CA 58 km (36 mi) ENE earthquakes near Contra Costa County
Alameda County, CA 63 km (39 mi) ESE earthquakes near Alameda County
Solano County, CA 78 km (48 mi) NE earthquakes near Solano County

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

Aftershocks so far

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

  1. 1.6 6km WSW of Colma, CA
  2. 2.5 4km N of San Leandro, CA
  3. 2.0 1km W of Kensington, CA
  4. 2.5 1km W of Kensington, CA
  5. 2.3 1km W of Kensington, CA
  6. 2.6 1km W of Kensington, CA
  7. 1.6 6km N of San Leandro, CA
  8. 1.5 2km SW of San Francisco Zoo, CA
  9. 1.6 4km ENE of Burlingame, CA
  10. 2.0 4km ENE of El Sobrante, CA
  11. 2.8 4km ENE of El Sobrante, CA
  12. 2.1 4km ENE of El Sobrante, CA
  13. 2.1 3km WNW of Crockett, CA
  14. 1.6 4km SSW of San Francisco Zoo, CA
  15. 2.1 4km WSW of Alamo, 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.