Earthquake · reviewed by a seismologist
M 1.5md
Earthquake near Angwin, CA
No earthquake was likely felt in Angwin in the 24 hours to 2:53 am PST (10:53 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 1.5 earthquake was recorded 15 km (9 mi) east of Angwin, CA, at 5:12 am PDT on 26 October 2020 (12:12 UTC), 5.6 km deep.
USGS: 15km E of Angwin, CA
88 km (55 mi) N of San Francisco, CA · 30 km (18 mi) N of Napa, CA
- When
- 5:12 am PDT on 26 October 2020 ()
- Where
- 15 km (9 mi) east of Angwin, CA · earthquakes near Angwin
- Magnitude
- M 1.5 (md)
- Depth
- 5.6 km below the surface
- Felt
- no reports yet
- Nearest
- Napa County, 8 km SW
- Nearest mapped fault
- Hunting Creek-Berryessa fault system, 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 2207 days ago
Earthquake alerts for Angwin, 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 9 km (6 mi) from the epicentre. In Angwin, 15 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: Deer Park, Saint Helena, Yountville, Calistoga, Esparto, Winters.
How big was it?
This earthquake released about 6.2 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 2,500,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
- Around the size people start to feel M 3.0 150× the energy of this one
- This earthquake M 1.5 about 6.2 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 4.2 on 2018-01-18 — about 10,000 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 6.0 The 2014 South Napa, California Earthquake · 39 km S of this epicentre
- 5.4 South of Elmira, California · 44 km SE 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 38.5628, -122.2763. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Napa County, CA | 8 km (5 mi) | SW | earthquakes near Napa County |
| Yolo County, CA | 35 km (22 mi) | ENE | earthquakes near Yolo County |
| Solano County, CA | 44 km (27 mi) | SE | earthquakes near Solano County |
| Sonoma County, CA | 57 km (35 mi) | W | earthquakes near Sonoma County |
| Colusa County, CA | 68 km (43 mi) | N | earthquakes near Colusa County |
| Marin County, CA | 70 km (44 mi) | SW | earthquakes near Marin County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
25 earthquakes have been recorded within 50 km since this one.
- 1.8 5km NNE of Windsor, CA
- 2.1 1km NW of The Geysers, CA
- 2.3 5km NNE of Windsor, CA
- 1.6 1km N of The Geysers, CA
- 2.0 4km N of Larkfield-Wikiup, CA
- 1.9 7km SE of Lower Lake, CA
- 1.9 3km SE of The Geysers, CA
- 1.7 3km SE of The Geysers, CA
- 1.6 2km NNE of The Geysers, CA
- 1.8 2km S of Angwin, CA
- 1.7 10km ENE of Hidden Valley Lake, CA
- 1.7 3km SW of Anderson Springs, CA
- 1.7 6km SW of Yountville, CA
- 2.5 2km WSW of Anderson Springs, CA
- 2.3 14km E of Angwin, 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.