Earthquake · reviewed by a seismologist
M 3.9mw
15km NNW of Lake Pillsbury, CA
- When
- Magnitude
- M 3.9 (mw)
- Depth
- 7.4 km below the surface
- Felt
- 14 reports · strongest reported intensity IV
- Measured shaking
- intensity III (ShakeMap)
- USGS impact alert
- green
- Nearest
- Mendocino County, 36 km WSW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1908 days ago
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 14 people have reported feeling it to USGS.
How big was it?
This earthquake released about 11 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 15,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 680× the energy of this one
- Magna, Utah 2020 M 5.7 480× the energy of this one
- This earthquake M 3.9 about 11 tons of TNT
- Around the size people start to feel M 3.0 this one released 23× more
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.
Where
Epicentre 39.5257, -123.0365. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Mendocino County, CA | 36 km (23 mi) | ENE of here | earthquakes near Mendocino County |
| Lake County, CA | 53 km (33 mi) | NNW of here | earthquakes near Lake County |
| Glenn County, CA | 55 km (34 mi) | W of here | earthquakes near Glenn County |
| Colusa County, CA | 79 km (49 mi) | WNW of here | earthquakes near Colusa County |
| Tehama County, CA | 96 km (60 mi) | SW of here | earthquakes near Tehama County |
| Sonoma County, CA | 112 km (69 mi) | N of here | earthquakes near Sonoma County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 1.6 7km ESE of Willits, CA
- 2.8 7km ESE of Willits, CA
- 2.5 7km ESE of Willits, CA
- 1.8 4km NNE of Lake Pillsbury, CA
- 2.7 15km ESE of Lake Pillsbury, CA
- 1.9 4km NNW of Laytonville, CA
- 1.8 10km SE of Willits, CA
- 1.6 8km ENE of Willits, CA
- 1.8 6km N of Lake Pillsbury, CA
- 1.8 16km NE of Upper Lake, CA
- 2.0 11km W of Alder Springs, CA
- 1.9 14km SE of Lake Pillsbury, CA
- 1.5 10km SE of Willits, CA
- 1.9 10km SE of Willits, CA
- 1.9 5km SSE of Redwood Valley, 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.
For this area
The largest earthquake within 50 km in our catalogue was M 5.1 on 2016-08-10 — it released about 59 times the energy of this one.
From the QuakeIndex catalogue, built from the USGS FDSN event service.
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.