164 km SE of Akutan, Alaska

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 82 km (51 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 7.6 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.8 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 22,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 1,000× the energy of this one
3. Magna, Utah 2020 M 5.7 710× the energy of this one
4. This earthquake M 3.8 about 7.6 tons of TNT
5. Around the size people start to feel M 3.0 this one released 16× more

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 5.1 on 2017-05-24 — about 89 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

1. 6.2 136 km SE of Akutan, Alaska · 46 km N of this epicentre Apr 1, 1946
2. 6.2 184 km SE of Akutan, Alaska · 48 km ENE of this epicentre Apr 6, 1946
3. 6.2 156 km SE of Akutan, Alaska · 19 km NNE of this epicentre Nov 12, 1946
4. 5.4 149 km SE of Akutan, Alaska · 16 km WNW of this epicentre Dec 1, 1998
5. 5.2 159 km SE of Akutan, Alaska · 42 km NE of this epicentre Jul 26, 2001

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 53.0274, -164.1352. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.1 141 km SE of Akutan, Alaska 10:28 UTC
2. 2.4 169 km SE of Akutan, Alaska 12:55 UTC
3. 2.5 164 km ESE of Akutan, Alaska 15:14 UTC
4. 1.9 168 km SE of Akutan, Alaska 11:23 UTC
5. 3.0 167 km ESE of Akutan, Alaska 10:28 UTC
6. 1.8 160 km ESE of Akutan, Alaska 09:44 UTC
7. 3.7 165 km ESE of Akutan, Alaska 09:17 UTC
8. 2.1 168 km ESE of Akutan, Alaska 08:56 UTC
9. 2.0 169 km SE of Akutan, Alaska 08:49 UTC
10. 3.6 168 km ESE of Akutan, Alaska 08:24 UTC
11. 3.6 168 km ESE of Akutan, Alaska 07:52 UTC
12. 3.5 164 km ESE of Akutan, Alaska 07:27 UTC
13. 1.9 162 km ESE of Akutan, Alaska 07:21 UTC
14. 2.0 167 km ESE of Akutan, Alaska 07:04 UTC
15. 3.2 161 km ESE of Akutan, Alaska 06:59 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 19:18 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.