Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near Angwin, CA
No earthquake was likely felt in Angwin in the 24 hours to 7:49 am PST (15:49 UTC). The last one was M 1.6, in Angwin, at 11:57 pm PDT on 10 October 2026, estimated intensity II (weak) in town. Every earthquake near Angwin
This page: a magnitude 1.6 earthquake was recorded in Angwin, CA, at 5:32 pm PST on 9 February 2023 (01:32 UTC), 5.9 km deep.
USGS: 2km SE of Angwin, CA
87 km (54 mi) N of San Francisco, CA · 27 km (17 mi) ENE of Santa Rosa, CA
- When
- 5:32 pm PST on 9 February 2023 ()
- Where
- in Angwin, CA · earthquakes near Angwin
- Magnitude
- M 1.6 (md)
- Depth
- 5.9 km below the surface
- Felt
- no reports yet
- Nearest
- Napa County, 12 km ESE
- Nearest mapped fault
- West Napa fault, 8 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 1370 days ago
Earthquake alerts for Angwin, CA
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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.
Likely felt in: Angwin in town, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 6.6 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 2,300,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
- Around the size people start to feel M 3.0 140× the energy of this one
- This earthquake M 1.6 about 6.6 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 5.0 on 2016-12-14 — about 150,000 times the energy of this one.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 6.0 The 2014 South Napa, California Earthquake · 40 km SSE of this epicentre
- 5.3 3 km E of Bloomfield, California · 42 km SW of this epicentre
- 5.3 Northern California · 43 km SW 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 38.5645, -122.4402. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Napa County, CA | 12 km (7 mi) | ESE | earthquakes near Napa County |
| Sonoma County, CA | 42 km (26 mi) | W | earthquakes near Sonoma County |
| Yolo County, CA | 48 km (30 mi) | ENE | earthquakes near Yolo County |
| Solano County, CA | 55 km (34 mi) | SE | earthquakes near Solano County |
| Marin County, CA | 63 km (39 mi) | SSW | earthquakes near Marin County |
| Lake County, CA | 66 km (41 mi) | NNW | earthquakes near Lake County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
60 earthquakes have been recorded within 50 km since this one.
- 1.7 8km NW of The Geysers, CA
- 2.0 8km NW of The Geysers, CA
- 2.9 5km WNW of The Geysers, CA
- 1.5 5km WNW of The Geysers, CA
- 2.2 3km SE of The Geysers, CA
- 1.6 7km W of Cobb, CA
- 1.8 7km WNW of Cobb, CA
- 1.5 2km NNE of The Geysers, CA
- 1.6 7km WNW of Cobb, CA
- 1.6 8km WNW of The Geysers, CA
- 1.8 8km W of Cobb, CA
- 2.2 1km NE of The Geysers, CA
- 1.7 1km NE of The Geysers, CA
- 1.5 4km W of Cobb, CA
- 2.0 8km NW of The Geysers, 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.