Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Hidden Valley Lake, CA
No earthquake was likely felt in Hidden Valley Lake in the 24 hours to 1:21 pm PST (21:21 UTC). The last one was M 2.6, 18 km (11 mi) W, at 4:44 pm PST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Hidden Valley Lake
This page: a magnitude 1.8 earthquake was recorded 9 km (6 mi) northeast of Hidden Valley Lake, CA, at 5:57 am PDT on 28 May 2021 (12:57 UTC), 7.7 km deep.
USGS: 9km NE of Hidden Valley Lake, CA
50 km (31 mi) NNE of Santa Rosa, CA · 121 km (75 mi) N of San Francisco, CA
- When
- 5:57 am PDT on 28 May 2021 ()
- Where
- 9 km (6 mi) northeast of Hidden Valley Lake, CA · earthquakes near Hidden Valley Lake
- Magnitude
- M 1.8 (md)
- Depth
- 7.7 km below the surface
- Felt
- no reports yet
- Nearest
- Lake County, 35 km NW
- Nearest mapped fault
- Hunting Creek-Berryessa fault system, 7 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 1993 days ago
Earthquake alerts for Hidden Valley Lake, CA
Get a notification in this browser when USGS records an earthquake near Hidden Valley Lake, 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 11 km (7 mi) from the epicentre. In Hidden Valley Lake, 9 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: Lower Lake, Clearlake, Middletown, Cobb, Clear Lake Riviera, Clearlake Oaks.
How big was it?
This earthquake released about 16 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 970,000× the energy of this one
- Magna, Utah 2020 M 5.7 680,000× the energy of this one
- Around the size people start to feel M 3.0 61× the energy of this one
- This earthquake M 1.8 about 16 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 63,000 times the energy of this one.
Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.
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 38.8645, -122.4838. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Lake County, CA | 35 km (22 mi) | NW | earthquakes near Lake County |
| Colusa County, CA | 41 km (25 mi) | NNE | earthquakes near Colusa County |
| Napa County, CA | 42 km (26 mi) | SSE | earthquakes near Napa County |
| Sonoma County, CA | 54 km (33 mi) | SW | earthquakes near Sonoma County |
| Yolo County, CA | 54 km (34 mi) | ESE | earthquakes near Yolo County |
| Sutter County, CA | 70 km (44 mi) | ENE | earthquakes near Sutter County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
59 earthquakes have been recorded within 50 km since this one.
- 1.6 6km SSW of Calistoga, CA
- 2.4 2km SW of Anderson Springs, CA
- 1.7 1km ESE of The Geysers, CA
- 1.8 6km ESE of Santa Rosa, CA
- 1.6 14km E of Angwin, CA
- 1.7 7km NW of The Geysers, CA
- 2.0 7km S of Anderson Springs, CA
- 2.3 6km NW of The Geysers, CA
- 1.8 6km NNW of The Geysers, CA
- 1.6 7km W of Cobb, CA
- 2.2 8km NW of The Geysers, CA
- 1.6 7km W of Cobb, CA
- 1.7 11km E of Hidden Valley Lake, CA
- 2.4 7km NW of The Geysers, CA
- 2.4 3km W of Cobb, 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.