Earthquake · reviewed by a seismologist
M 5.1mw
12km W of Petrolia, CA
- When
- Magnitude
- M 5.1 (mw)
- Depth
- 31 km below the surface
- Felt
- 751 reports · strongest reported intensity IV
- Measured shaking
- intensity IV (ShakeMap)
- USGS impact alert
- green
- Nearest
- Humboldt County, 60 km NE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 279 days ago
This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre. 751 people have reported feeling it to USGS.
How big was it?
This earthquake released about 720 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.1 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 230× the energy of this one
- Mineral, Virginia 2011 M 5.8 10× the energy of this one
- Magna, Utah 2020 M 5.7 7.4× the energy of this one
- This earthquake M 5.1 about 720 tons of TNT
- Around the size people start to feel M 3.0 this one released 1,500× 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 40.3235, -124.4255. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Humboldt County, CA | 60 km (37 mi) | SW of here | earthquakes near Humboldt County |
| Trinity County, CA | 117 km (72 mi) | WSW of here | earthquakes near Trinity County |
| Mendocino County, CA | 130 km (81 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
58 earthquakes have been recorded within 50 km since this one.
- 2.2 8km WSW of Petrolia, CA
- 4.5 10km SW of Petrolia, CA
- 1.5 9km WSW of Petrolia, CA
- 2.5 36km W of Petrolia, CA
- 2.5 8km WSW of Petrolia, CA
- 1.9 6km WSW of Petrolia, CA
- 1.8 6km W of Petrolia, CA
- 2.3 7km W of Petrolia, CA
- 2.6 50km W of Petrolia, CA
- 2.4 8km W of Petrolia, CA
- 3.5 11km WSW of Petrolia, CA
- 4.0 11km WSW of Petrolia, CA
- 2.4 22km NW of Petrolia, CA
- 1.7 12km SSW of Ferndale, CA
- 1.7 12km SSW 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 5.6 on 2019-06-23 — 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.