Earthquake · reviewed by a seismologist
M 2.7md
46 km W of Petrolia, CA
Yes. A magnitude 2.7 earthquake was recorded 46 km W of Petrolia, CA, at 6:55 am PDT on 20 March 2024 (13:55 UTC), 25 km deep.
- When
- Magnitude
- M 2.7 (md)
- Depth
- 25 km below the surface
- Felt
- no reports yet
- Nearest
- Humboldt County, 85 km ENE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 899 days ago
Earthquake alerts for Ferndale, CA
Get a notification in this browser when USGS records an earthquake near Ferndale, 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 small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 2 km (1 mi) from the epicentre. 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.
How big was it?
This earthquake released about 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
- Magna, Utah 2020 M 5.7 32,000× the energy of this one
- Around the size people start to feel M 3.0 2.8× the energy of this one
- This earthquake M 2.7 about 340 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 6.4 on 2022-12-20 — about 350,000 times the energy of this one.
Before 2016, the USGS record lists 36 earthquakes of M5 or more within 50 km; the five largest:
- 6.6 32 km SW of Ferndale, California · 23 km E of this epicentre
- 6.5 30 km WSW of Ferndale, California · 23 km ENE of this epicentre
- 6.5 The 2010 Eureka, California Earthquake · 34 km NNE of this epicentre
- 6.0 Offshore Humboldt County, California · 43 km SSW of this epicentre
- 6.0 53 km SW of Ferndale, California · 17 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 40.3617, -124.8252. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Humboldt County, CA | 85 km (53 mi) | ENE | earthquakes near Humboldt County |
| Mendocino County, CA | 157 km (97 mi) | SE | 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.
- 2.0 18 km WNW of Petrolia, CA
- 2.1 15 km WSW of Ferndale, CA
- 1.9 24 km NW of Petrolia, CA
- 1.8 19 km W of Petrolia, CA
- 3.0 14 km WSW of Ferndale, CA
- 1.9 26 km W of Petrolia, CA
- 3.0 52 km WNW of Petrolia, CA
- 1.6 8 km S of Petrolia, CA
- 2.3 53 km W of Ferndale, CA
- 2.7 81 km WNW of Petrolia, CA
- 1.5 24 km W of Petrolia, CA
- 2.8 30 km W of Petrolia, CA
- 2.6 60 km W of Ferndale, CA
- 2.0 9 km of Petrolia, CA
- 2.4 81 km WNW 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.
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.