Earthquake · reviewed by a seismologist
M 3.7mw
12km WSW of Petrolia, CA
- When
- Magnitude
- M 3.7 (mw)
- Depth
- 7.9 km below the surface
- Felt
- 24 reports · strongest reported intensity IV
- Measured shaking
- intensity IV (ShakeMap)
- Nearest
- Humboldt County, 62 km NE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1161 days ago
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 24 people have reported feeling it to USGS.
How big was it?
This earthquake released about 5.2 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.7 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 33,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 1,500× the energy of this one
- Magna, Utah 2020 M 5.7 1,000× the energy of this one
- This earthquake M 3.7 about 5.2 tons of TNT
- Around the size people start to feel M 3.0 this one released 11× 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 40.2942, -124.4145. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Humboldt County, CA | 62 km (38 mi) | SW of here | earthquakes near Humboldt County |
| Trinity County, CA | 117 km (73 mi) | WSW of here | earthquakes near Trinity County |
| Mendocino County, CA | 127 km (79 mi) | NW of here | earthquakes near Mendocino County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
56 earthquakes have been recorded within 50 km since this one.
- 3.0 4km WNW of Ferndale, CA
- 2.3 4km ESE of Fortuna, CA
- 2.7 7km SW of Ferndale, CA
- 2.1 7km ESE of Hydesville, CA
- 2.8 2km E of Fortuna, CA
- 2.5 7km NNE of Hydesville, CA
- 2.8 14km WSW of Ferndale, CA
- 2.9 4 km NE of Fortuna, CA
- 2.9 6 km SW of Ferndale, CA
- 4.9 7km WNW of Rio Dell, CA
- 6.4 15km WSW of Ferndale, CA
- 2.2 16km SE of Petrolia, CA
- 2.5 36km WNW of Petrolia, CA
- 2.8 49km WSW of Ferndale, CA
- 2.4 24km WSW of Ferndale, 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 6.2 on 2021-12-20 — it released about 5,800 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.