Earthquake · reviewed by a seismologist
M 2.6md
Earthquake near Eureka, CA
No earthquake was likely felt in Eureka in the 24 hours to 11:29 am PST (19:29 UTC). The last one was M 5.0, 128 km (79 mi) WSW, at 8:56 pm PST on 4 November 2026, estimated intensity II (weak) in town; 145 felt reports to USGS. Every earthquake near Eureka
This page: a magnitude 2.6 earthquake was recorded 39 km (24 mi) west-southwest of Eureka, CA, at 12:33 pm PDT on 28 April 2021 (19:33 UTC), 23 km deep. 2 people have reported feeling it to USGS.
USGS: 32km WNW of Ferndale, CA
- When
- 12:33 pm PDT on 28 April 2021 ()
- Where
- 39 km (24 mi) west-southwest of Eureka, CA · earthquakes near Eureka
- Magnitude
- M 2.6 (md)
- Depth
- 23 km below the surface
- Felt
- 2 reports · strongest reported intensity III
- Nearest
- Humboldt County, 57 km E
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1954 days ago
Earthquake alerts for Eureka, CA
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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 8 km (5 mi) from the epicentre. In Eureka, 39 km away, the estimate is intensity II (weak). 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 250 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 61,000× the energy of this one
- Magna, Utah 2020 M 5.7 43,000× the energy of this one
- Around the size people start to feel M 3.0 3.8× the energy of this one
- This earthquake M 2.6 about 250 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 5.2 on 2020-03-18 — about 7,900 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 · 35 km S of this epicentre
- 6.5 The 1932 Eureka, California Earthquake · 27 km E of this epicentre
- 6.5 30 km WSW of Ferndale, California · 29 km S of this epicentre
- 6.5 The 2010 Eureka, California Earthquake · 8 km WSW of this epicentre
- 6.4 Northwest of Eureka, California · 36 km NNE 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 40.6910, -124.6067. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Humboldt County, CA | 57 km (36 mi) | E | earthquakes near Humboldt County |
| Del Norte County, CA | 129 km (80 mi) | NNE | earthquakes near Del Norte 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.
- 2.7 7km W of Petrolia, CA
- 2.7 33km WNW of Petrolia, CA
- 2.8 40km WNW of Petrolia, CA
- 1.7 16km SW of Ferndale, CA
- 2.8 56km WNW of Petrolia, CA
- 4.3 12km WSW of Petrolia, CA
- 2.1 4km SW of Petrolia, CA
- 2.4 9km W of Petrolia, CA
- 5.1 12km W of Petrolia, CA
- 2.4 21km W of Petrolia, CA
- 2.4 8km WSW of Petrolia, CA
- 1.8 9km SSW of Ferndale, CA
- 1.6 9km SSW of Ferndale, CA
- 1.7 9km SSW of Ferndale, CA
- 3.4 57km 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.