Earthquake · reviewed by a seismologist
M 1.5md
Earthquake near San Francisco, CA
No earthquake was likely felt in San Francisco in the 24 hours to 1:49 am PST (09:49 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 1.5 earthquake was recorded 11 km (7 mi) southwest of San Francisco, CA, at 7:32 pm PDT on 31 October 2021 (02:32 UTC), 7.3 km deep. 1 person has reported feeling it to USGS.
USGS: 2km SW of San Francisco Zoo, CA
11 km (7 mi) SW of San Francisco, CA · 5 km (3 mi) WNW of Daly City, CA
- When
- 7:32 pm PDT on 31 October 2021 ()
- Where
- 11 km (7 mi) southwest of San Francisco, CA · earthquakes near San Francisco
- Magnitude
- M 1.5 (md)
- Depth
- 7.3 km below the surface
- Felt
- 1 report · strongest reported intensity II
- Nearest
- San Mateo County, 36 km SSE
- 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 1829 days ago
Earthquake alerts for San Francisco, CA
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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 7 km (4 mi) from the epicentre. In San Francisco, 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.
Likely felt in: Daly City 6 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
- Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
- Around the size people start to feel M 3.0 180× the energy of this one
- This earthquake M 1.5 about 5.4 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 4.5 on 2019-10-15 — about 28,000 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 7.9 The 1906 San Francisco, California Earthquake · 4 km NNW of this epicentre
- 5.3 The 1957 San Francisco, California Earthquake · 7 km SSE 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 37.7172, -122.5238. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| San Mateo County, CA | 36 km (23 mi) | SSE | earthquakes near San Mateo County |
| Marin County, CA | 42 km (26 mi) | NNW | earthquakes near Marin County |
| San Francisco County, CA | 45 km (28 mi) | W | earthquakes near San Francisco County |
| Alameda County, CA | 54 km (34 mi) | E | earthquakes near Alameda County |
| Contra Costa County, CA | 55 km (34 mi) | ENE | earthquakes near Contra Costa County |
| Solano County, CA | 80 km (50 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.
- 2.1 3km NE of Berkeley, CA
- 2.0 2km E of Hayward, CA
- 1.6 2km E of Hayward, CA
- 1.6 2km ESE of Hayward, CA
- 1.9 4km NNW of Crockett, CA
- 2.3 4km SSE of Vallejo, CA
- 2.8 1km ENE of El Cerrito, CA
- 1.6 2km NNE of Danville, 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 2km NE of Union City, CA
- 1.8 3km ENE of San Leandro, CA
- 2.9 3km ENE of San Leandro, CA
- 1.6 2km ENE of Pacifica, 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.