Earthquake · reviewed by a seismologist
M 2.6md
45km W of Petrolia, CA
Yes. A magnitude 2.6 earthquake was recorded 45km W of Petrolia, CA, at 2:09 pm PDT on 23 August 2020 (21:09 UTC), 22 km deep.
- When
- Magnitude
- M 2.6 (md)
- Depth
- 22 km below the surface
- Felt
- no reports yet
- Nearest
- Humboldt County, 84 km ENE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2203 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 11 km (7 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 280 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 55,000× the energy of this one
- Magna, Utah 2020 M 5.7 39,000× the energy of this one
- Around the size people start to feel M 3.0 3.5× the energy of this one
- This earthquake M 2.6 about 280 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 5.8 on 2020-03-09 — about 50,000 times the energy of this one.
Before 2016, the USGS record lists 38 earthquakes of M5 or more within 50 km; the five largest:
- 7.2 The 1992 Petrolia, California Earthquake · 49 km E of this epicentre
- 6.6 32 km SW of Ferndale, California · 22 km E of this epicentre
- 6.5 30 km WSW of Ferndale, California · 22 km ENE of this epicentre
- 6.5 The 2010 Eureka, California Earthquake · 34 km NNE of this epicentre
- 6.0 Offshore Humboldt County, California · 44 km SSW 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 40.3640, -124.8113. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Humboldt County, CA | 84 km (52 mi) | ENE | earthquakes near Humboldt County |
| Mendocino County, CA | 156 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
57 earthquakes have been recorded within 50 km since this one.
- 2.1 21km NW of Petrolia, CA
- 1.7 7km WNW of Petrolia, CA
- 2.7 60km W of Ferndale, CA
- 2.1 23km NW of Petrolia, CA
- 3.1 52km W of Petrolia, CA
- 2.5 50km W of Petrolia, CA
- 2.6 26km W of Petrolia, CA
- 2.8 19km W of Petrolia, CA
- 2.7 26km WNW of Petrolia, CA
- 2.7 8km WSW of Petrolia, CA
- 1.8 12km SSW of Ferndale, CA
- 2.4 33km W of Petrolia, CA
- 2.4 11km WSW of Petrolia, CA
- 3.5 12km WSW of Petrolia, CA
- 2.0 17km W of Petrolia, 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.