212 km W of Bandon, Oregon

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 30 km (19 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 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
3. Around the size people start to feel M 3.0 1.4× the energy of this one
4. This earthquake M 2.9 about 680 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 5.7 on 2020-12-29 — about 16,000 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 43.4439, -126.9870. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.9 239 km W of Langlois, Oregon 01:47 UTC
2. 2.9 195 km W of Port Orford, Oregon 09:23 UTC
3. 3.0 227 km W of Bandon, Oregon 12:52 UTC
4. 2.9 226 km W of Bandon, Oregon 02:01 UTC
5. 2.6 197 km W of Bandon, Oregon 06:09 UTC
6. 2.8 195 km W of Bandon, Oregon 19:38 UTC
7. 2.7 198 km WNW of Barview, Oregon 23:27 UTC
8. 2.9 258 km WNW of Bandon, Oregon 23:19 UTC
9. 2.9 189 km W of Bandon, Oregon 23:07 UTC
10. 3.9 249 km W of Bandon, Oregon 19:28 UTC
11. 3.2 232 km W of Bandon, Oregon 13:52 UTC
12. 3.9 196 km W of Bandon, Oregon 09:44 UTC
13. 3.2 191 km W of Bandon, Oregon 22:21 UTC
14. 3.2 231 km WNW of Bandon, Oregon 11:22 UTC
15. 3.2 211 km W of Bandon, Oregon 01:37 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 19:16 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.