160 km W of Ferndale, California

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 17 km (11 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 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
3. Around the size people start to feel M 3.0 11× the energy of this one
4. This earthquake M 2.3 about 85 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 6.6 on 2016-12-08 — about 2,800,000 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 40.4310, -126.1506. Map © OpenStreetMap contributors.

Aftershocks so far

49 earthquakes have been recorded within 50 km since this one.

1. 2.6 145 km W of Ferndale, California 23:02 UTC
2. 2.5 157 km W of Ferndale, California 10:53 UTC
3. 2.8 194 km W of Ferndale, California 02:18 UTC
4. 2.6 173 km W of Ferndale, California 05:34 UTC
5. 2.7 136 km W of Ferndale, California 07:25 UTC
6. 3.8 161 km W of Ferndale, California 15:29 UTC
7. 2.9 137 km W of Petrolia, CA 14:06 UTC
8. 2.6 155 km W of Ferndale, California 02:06 UTC
9. 3.0 151 km W of Ferndale, California 11:17 UTC
10. 2.6 149 km W of Ferndale, California 13:07 UTC
11. 2.7 171 km W of Ferndale, California 02:17 UTC
12. 2.9 162 km W of Ferndale, California 04:42 UTC
13. 3.0 134 km W of Petrolia, CA 06:48 UTC
14. 3.2 175 km W of Ferndale, California 09:42 UTC
15. 2.6 156 km W of Ferndale, California 16:24 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 12:11 UTC. 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.