Earthquake · reviewed by a seismologist
M 4.0mw
20km ENE of Redway, CA
- When
- Magnitude
- M 4.0 (mw)
- Depth
- 34 km below the surface
- Felt
- 26 reports · strongest reported intensity IV
- Measured shaking
- intensity III (ShakeMap)
- USGS impact alert
- green
- Nearest
- Humboldt County, 64 km NNW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1912 days ago
This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 26 people have reported feeling it to USGS.
How big was it?
This earthquake released about 17 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 10,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 450× the energy of this one
- Magna, Utah 2020 M 5.7 320× the energy of this one
- This earthquake M 4.0 about 17 tons of TNT
- Around the size people start to feel M 3.0 this one released 35× 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 40.1880, -123.5988. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Humboldt County, CA | 64 km (40 mi) | SSE of here | earthquakes near Humboldt County |
| Trinity County, CA | 66 km (41 mi) | SW of here | earthquakes near Trinity County |
| Mendocino County, CA | 85 km (53 mi) | N of here | earthquakes near Mendocino County |
| Tehama County, CA | 116 km (72 mi) | W of here | earthquakes near Tehama County |
| Glenn County, CA | 121 km (75 mi) | WNW of here | earthquakes near Glenn County |
| Colusa County, CA | 162 km (101 mi) | NW of here | earthquakes near Colusa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
49 earthquakes have been recorded within 50 km since this one.
- 2.0 16km NNE of Redway, CA
- 1.7 15km ESE of Hydesville, CA
- 1.9 14km NNE of Laytonville, CA
- 1.8 20km SSE of Rio Dell, CA
- 1.9 20km SSE of Rio Dell, CA
- 2.3 20km NNE of Redway, CA
- 2.6 15km SE of Petrolia, CA
- 1.7 2km N of Redway, CA
- 4.1 19km NW of Covelo, CA
- 2.0 28km NE of Redway, CA
- 1.6 5km NW of Redway, CA
- 1.9 8km SSE of Redway, CA
- 2.0 8km SSE of Redway, CA
- 1.8 18km E of Rio Dell, CA
- 2.0 18km E of Rio Dell, 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 4.5 on 2016-08-28 — it released about 4.9 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.