Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Bolinas, CA
No earthquake was likely felt in Bolinas in the 24 hours to 6:44 am PST (14:44 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 1.7 earthquake was recorded in Bolinas, CA, at 10:04 am PDT on 5 September 2021 (17:04 UTC), 8.8 km deep.
USGS: 1km N of Bolinas, CA
28 km (18 mi) NW of San Francisco, CA · 17 km (11 mi) WSW of San Rafael, CA
- When
- 10:04 am PDT on 5 September 2021 ()
- Where
- in Bolinas, CA · earthquakes near Bolinas
- Magnitude
- M 1.7 (md)
- Depth
- 8.8 km below the surface
- Felt
- no reports yet
- Nearest
- Marin County, 15 km NNW
- Nearest mapped fault
- San Andreas 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 1889 days ago
Earthquake alerts for Bolinas, CA
Get a notification in this browser when USGS records an earthquake near Bolinas, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 9 km (6 mi) from the epicentre. 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: Lagunitas-Forest Knolls, Woodacre, Fairfax, Kentfield, Ross, San Anselmo.
How big was it?
This earthquake released about 11 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.
- Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
- Around the size people start to feel M 3.0 89× the energy of this one
- This earthquake M 1.7 about 11 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 10,000 times the energy of this one.
Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:
- 7.9 The 1906 San Francisco, California Earthquake · 22 km SSE of this epicentre
- 6.0 The 2014 South Napa, California Earthquake · 46 km NE of this epicentre
- 5.3 The 1957 San Francisco, California Earthquake · 33 km SSE of this epicentre
- 5.3 3 km E of Bloomfield, California · 45 km NNW of this epicentre
- 5.3 Northern California · 46 km NNW 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 37.9208, -122.6857. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Marin County, CA | 15 km (10 mi) | NNW | earthquakes near Marin County |
| San Francisco County, CA | 37 km (23 mi) | SW | earthquakes near San Francisco County |
| San Mateo County, CA | 63 km (39 mi) | SSE | earthquakes near San Mateo County |
| Contra Costa County, CA | 64 km (40 mi) | E | earthquakes near Contra Costa County |
| Sonoma County, CA | 70 km (44 mi) | NNW | earthquakes near Sonoma County |
| Napa County, CA | 72 km (45 mi) | NNE | earthquakes near Napa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
50 earthquakes have been recorded within 50 km since this one.
- 1.7 5km E of Vallejo, CA
- 1.6 5km E of Vallejo, CA
- 1.6 7km S of Muir Beach, CA
- 1.8 3km SW of San Francisco Zoo, CA
- 1.5 5km E of Vallejo, CA
- 2.1 3km NE of Berkeley, CA
- 1.9 4km NNW of Crockett, CA
- 1.8 3km W of American Canyon, CA
- 2.3 4km SSE of Vallejo, CA
- 2.8 1km ENE of El Cerrito, CA
- 1.6 5km E of Vallejo, CA
- 1.7 6km WSW of Daly City, CA
- 1.6 4km E of South San Francisco, CA
- 1.5 5km WSW of Daly City, CA
- 1.6 4km N of Inverness, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.