207 km SE of Perryville, Alaska

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. 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 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
2. Magna, Utah 2020 M 5.7 32,000× the energy of this one
3. Around the size people start to feel M 3.0 2.8× the energy of this one
4. This earthquake M 2.7 about 340 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 5.0 on 2023-01-10 — about 2,800 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

1. 5.9 182 km SE of Perryville, Alaska · 26 km WNW of this epicentre Dec 23, 1938
2. 5.5 160 km SE of Perryville, Alaska · 48 km NNW of this epicentre Mar 10, 2012
3. 5.0 176 km SSE of Chignik, Alaska · 49 km N of this epicentre Jul 21, 1982
4. 5.0 213 km SE of Perryville, Alaska · 21 km ENE of this epicentre Jan 7, 2007

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 54.5179, -156.9852. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.5 198 km SE of Perryville, Alaska 20:34 UTC
2. 3.1 188 km SE of Perryville, Alaska 22:48 UTC
3. 3.2 202 km SE of Perryville, Alaska 16:22 UTC
4. 3.5 184 km SE of Perryville, Alaska 19:49 UTC
5. 3.0 179 km SE of Perryville, Alaska 22:53 UTC
6. 3.1 194 km SE of Perryville, Alaska 03:40 UTC
7. 4.8 184 km SE of Perryville, Alaska 15:16 UTC
8. 3.2 196 km SE of Perryville, Alaska 07:55 UTC
9. 3.1 202 km SE of Perryville, Alaska 16:51 UTC
10. 2.9 186 km SE of Perryville, Alaska 04:23 UTC
11. 3.6 193 km SE of Perryville, Alaska 04:13 UTC
12. 3.9 197 km SE of Perryville, Alaska 04:11 UTC
13. 2.8 199 km SE of Perryville, Alaska 20:49 UTC
14. 2.9 200 km SE of Perryville, Alaska 20:30 UTC
15. 2.5 180 km SE of Perryville, Alaska 06:55 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 15:49 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.