Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near San Francisco, CA
No earthquake was likely felt in San Francisco in the 24 hours to 4:42 am PST (12:42 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 1.6 earthquake was recorded 14 km (9 mi) west of San Francisco, CA, at 5:41 pm PDT on 24 July 2021 (00:41 UTC), 4.9 km deep.
USGS: 8km S of Muir Beach, CA
14 km (9 mi) W of San Francisco, CA
- When
- 5:41 pm PDT on 24 July 2021 ()
- Where
- 14 km (9 mi) west of San Francisco, CA · earthquakes near San Francisco
- Magnitude
- M 1.6 (md)
- Depth
- 4.9 km below the surface
- Felt
- no reports yet
- Nearest
- Marin County, 32 km NNW
- Nearest mapped fault
- San Andreas fault, 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 1926 days ago
Earthquake alerts for San Francisco, CA
Get a notification in this browser when USGS records an earthquake near San Francisco, 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 10 km (6 mi) from the epicentre. In San Francisco, 14 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: Tamalpais-Homestead Valley 10 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 7.8 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,900,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
- Around the size people start to feel M 3.0 120× the energy of this one
- This earthquake M 1.6 about 7.8 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 19,000 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 · 5 km SSE of this epicentre
- 5.3 The 1957 San Francisco, California Earthquake · 16 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 37.7935, -122.5757. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Marin County, CA | 32 km (20 mi) | NNW | earthquakes near Marin County |
| San Francisco County, CA | 41 km (25 mi) | W | earthquakes near San Francisco County |
| San Mateo County, CA | 46 km (28 mi) | SSE | earthquakes near San Mateo County |
| Contra Costa County, CA | 57 km (35 mi) | ENE | earthquakes near Contra Costa County |
| Alameda County, CA | 61 km (38 mi) | ESE | earthquakes near Alameda County |
| Solano County, CA | 77 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.
- 1.6 3km SSW of Half Moon Bay, CA
- 2.2 3km SSW of Half Moon Bay, CA
- 1.6 7km WSW of Lagunitas-Forest Knolls, CA
- 1.6 3km SSW of Half Moon Bay, CA
- 1.6 6km WSW of Colma, CA
- 2.5 4km N of San Leandro, CA
- 2.0 1km W of Kensington, CA
- 2.5 1km W of Kensington, CA
- 2.3 1km W of Kensington, CA
- 2.6 1km W of Kensington, CA
- 1.6 6km N of San Leandro, CA
- 1.5 2km SW of San Francisco Zoo, CA
- 1.6 4km ENE of Burlingame, CA
- 1.6 1km SW of Alamo, CA
- 2.0 4km ENE of El Sobrante, 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.