Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Angwin, CA
No earthquake was likely felt in Angwin in the 24 hours to 3:07 am PST (11:07 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 1.7 earthquake was recorded 15 km (9 mi) east of Angwin, CA, at 6:38 am PST on 18 December 2019 (14:38 UTC), 2.6 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
- 6:38 am PST on 18 December 2019 ()
- Where
- 15 km (9 mi) east of Angwin, CA · earthquakes near Angwin
- Magnitude
- M 1.7 (md)
- Depth
- 2.6 km below the surface
- Felt
- no reports yet
- Nearest
- Napa County, 7 km SSW
- 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 2442 days ago
Earthquake alerts for Angwin, CA
Get a notification in this browser when USGS records an earthquake near Angwin, 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 12 km (7 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 9.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
- Around the size people start to feel M 3.0 99× the energy of this one
- This earthquake M 1.7 about 9.6 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 4.2 on 2018-01-18 — about 6,700 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 38.5643, -122.2815. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Napa County, CA | 7 km (5 mi) | SSW | earthquakes near Napa County |
| Yolo County, CA | 35 km (22 mi) | ENE | earthquakes near Yolo County |
| Solano County, CA | 44 km (28 mi) | SE | earthquakes near Solano County |
| Sonoma County, CA | 56 km (35 mi) | W | earthquakes near Sonoma County |
| Colusa County, CA | 68 km (42 mi) | N | earthquakes near Colusa County |
| Marin County, CA | 70 km (43 mi) | SW | earthquakes near Marin County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
31 earthquakes have been recorded within 50 km since this one.
- 1.7 4km SE of The Geysers, CA
- 1.6 14km ESE of Hidden Valley Lake, CA
- 1.8 4km SW of Anderson Springs, CA
- 1.8 2km SSW of Cobb, CA
- 2.5 12km ESE of Angwin, CA
- 2.0 4km NNW of Larkfield-Wikiup, CA
- 1.9 4km SSE of Elmira, CA
- 2.1 11km ENE of Hidden Valley Lake, CA
- 1.6 1km NNW of The Geysers, CA
- 1.8 5km NNW of Green Valley, CA
- 1.7 14km ENE of Hidden Valley Lake, CA
- 1.8 2km NNW of The Geysers, CA
- 1.8 3km SW of Anderson Springs, CA
- 1.6 5km NE of Kenwood, CA
- 2.3 16km SE of Hidden Valley Lake, 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.