Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Redwood Valley, CA
No earthquake was likely felt in Redwood Valley in the 24 hours to 8:52 am PST (16:52 UTC). The last one was M 1.5, 7 km (5 mi) SE, at 12:31 pm PST on 11 November 2026, estimated intensity II (weak) in town. Every earthquake near Redwood Valley
This page: a magnitude 1.7 earthquake was recorded 5 km (3 mi) west-southwest of Redwood Valley, CA, at 10:11 pm PDT on 10 May 2021 (05:11 UTC), 2.1 km deep.
USGS: 5km WSW of Redwood Valley, CA
- When
- 10:11 pm PDT on 10 May 2021 ()
- Where
- 5 km (3 mi) west-southwest of Redwood Valley, CA · earthquakes near Redwood Valley
- Magnitude
- M 1.7 (md)
- Depth
- 2.1 km below the surface
- Felt
- no reports yet
- Nearest
- Mendocino County, 27 km NW
- Nearest mapped fault
- Maacama fault, 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 2011 days ago
Earthquake alerts for Redwood Valley, CA
Get a notification in this browser when USGS records an earthquake near Redwood Valley, 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 13 km (8 mi) from the epicentre. In Redwood Valley, 5 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.
Likely felt in: Ukiah 11 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 12 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 1,200,000× the energy of this one
- Magna, Utah 2020 M 5.7 870,000× the energy of this one
- Around the size people start to feel M 3.0 78× the energy of this one
- This earthquake M 1.7 about 12 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 5.1 on 2016-08-10 — about 110,000 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.2 6 km ESE of Talmage, California · 19 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 39.2397, -123.2562. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Mendocino County, CA | 27 km (17 mi) | NW | earthquakes near Mendocino County |
| Lake County, CA | 46 km (29 mi) | ESE | earthquakes near Lake County |
| Glenn County, CA | 84 km (52 mi) | ENE | earthquakes near Glenn County |
| Sonoma County, CA | 84 km (52 mi) | SSE | earthquakes near Sonoma County |
| Colusa County, CA | 88 km (55 mi) | E | earthquakes near Colusa County |
| Napa County, CA | 115 km (71 mi) | SE | earthquakes near Napa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
22 earthquakes have been recorded within 50 km since this one.
- 1.9 4km NNW of Lake Pillsbury, CA
- 1.8 6km E of Willits, CA
- 1.8 9km NNW of Redwood Valley, CA
- 2.2 7km E of Willits, CA
- 1.7 10km SW of Ukiah, CA
- 1.6 7km E of Willits, CA
- 1.6 9km NNW of Redwood Valley, CA
- 1.7 8km NNW of Redwood Valley, CA
- 1.7 19km SW of Laytonville, CA
- 1.9 15km N of Brooktrails, CA
- 2.9 4km SSE of Redwood Valley, CA
- 2.0 12km WNW of Redwood Valley, CA
- 1.8 10km NNW of Redwood Valley, CA
- 1.6 11km NNE of Boonville, CA
- 1.5 18km NNW of Cloverdale, 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.