184 km WSW of Pistol River, 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 5.6 on 2018-07-24 — about 11,000 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 41.8056, -126.5359. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.9 209 km WSW of Pistol River, Oregon 22:26 UTC
2. 2.8 193 km WSW of Pistol River, Oregon 17:49 UTC
3. 2.6 195 km WSW of Pistol River, Oregon 13:00 UTC
4. 2.6 199 km WSW of Pistol River, Oregon 04:14 UTC
5. 2.9 207 km WSW of Pistol River, Oregon 06:42 UTC
6. 2.6 186 km W of Pistol River, Oregon 17:59 UTC
7. 2.5 152 km WSW of Pistol River, Oregon 19:35 UTC
8. 5.7 143 km WSW of Pistol River, Oregon 10:53 UTC
9. 2.7 199 km W of Pistol River, Oregon 15:08 UTC
10. 3.4 233 km WSW of Pistol River, Oregon 05:31 UTC
11. 3.1 204 km WSW of Pistol River, Oregon 08:15 UTC
12. 3.7 145 km WSW of Pistol River, Oregon 04:26 UTC
13. 2.9 189 km WSW of Pistol River, Oregon 05:28 UTC
14. 3.5 155 km W of Pistol River, Oregon 05:27 UTC
15. 3.2 210 km WSW of Pistol River, Oregon 05:26 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 12:01 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.