Earthquake · reviewed by a seismologist
M 2.3md
Earthquake near Santa Rosa, CA
No earthquake was likely felt in Santa Rosa in the 24 hours to 4:35 am PST (12:35 UTC). The last one was M 1.9, 5 km (3 mi) NE, at 2:01 pm PDT on 23 October 2026, estimated intensity II (weak) in town. Every earthquake near Santa Rosa
This page: a magnitude 2.3 earthquake was recorded 28 km (17 mi) southwest of Santa Rosa, CA, at 7:59 pm PDT on 11 August 2021 (02:59 UTC), 4.0 km deep. 17 people have reported feeling it to USGS.
USGS: 2km WNW of Tomales, CA
68 km (43 mi) NW of San Francisco, CA · 25 km (16 mi) W of Petaluma, CA
- When
- 7:59 pm PDT on 11 August 2021 ()
- Where
- 28 km (17 mi) southwest of Santa Rosa, CA · earthquakes near Santa Rosa
- Magnitude
- M 2.3 (md)
- Depth
- 4.0 km below the surface
- Felt
- 17 reports · strongest reported intensity IV
- Nearest
- Marin County, 27 km SE
- Nearest mapped fault
- San Andreas fault, 5 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 1912 days ago
Earthquake alerts for Santa Rosa, CA
Get a notification in this browser when USGS records an earthquake near Santa Rosa, 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 19 km (12 mi) from the epicentre. In Santa Rosa, 28 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: Bodega Bay, Occidental, Inverness, Sebastopol, Camp Meeker, Cotati.
How big was it?
This earthquake released about 79 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 190,000× the energy of this one
- Magna, Utah 2020 M 5.7 130,000× the energy of this one
- Around the size people start to feel M 3.0 12× the energy of this one
- This earthquake M 2.3 about 79 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 5.3 3 km E of Bloomfield, California · 12 km NE of this epicentre
- 5.3 Northern California · 11 km NE 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 38.2515, -122.9205. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Marin County, CA | 27 km (17 mi) | SE | earthquakes near Marin County |
| Sonoma County, CA | 30 km (19 mi) | N | earthquakes near Sonoma County |
| Napa County, CA | 59 km (37 mi) | ENE | earthquakes near Napa County |
| San Francisco County, CA | 59 km (37 mi) | S | earthquakes near San Francisco County |
| Solano County, CA | 86 km (53 mi) | E | earthquakes near Solano County |
| Contra Costa County, CA | 92 km (57 mi) | ESE | earthquakes near Contra Costa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
55 earthquakes have been recorded within 50 km since this one.
- 1.6 13km ENE of Healdsburg, CA
- 1.9 7km NNE of Penngrove, CA
- 1.6 6km ESE of Penngrove, CA
- 1.5 6km NE of Santa Rosa, CA
- 2.2 6km ESE of Penngrove, CA
- 1.7 5km SSW of Calistoga, CA
- 2.1 10km NNE of Larkfield-Wikiup, CA
- 1.8 6km W of Glen Ellen, CA
- 1.9 6km ENE of Kenwood, CA
- 2.1 7km NE of Rohnert Park, CA
- 1.9 7km WSW of St. Helena, CA
- 1.9 9km NNE of Healdsburg, CA
- 2.2 5km WSW of Kenwood, CA
- 1.6 8km ENE of Healdsburg, CA
- 2.1 5km WSW of Kenwood, 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.