135 km S of Unalaska, Alaska

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 10 km (6 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 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
3. Around the size people start to feel M 3.0 63× the energy of this one
4. This earthquake M 1.8 about 15 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 5.9 on 2017-05-24 — about 1,400,000 times the energy of this one.

Before 2016, the USGS record lists 51 earthquakes of M5 or more within 50 km; the five largest:

1. 7.0 Fox Islands, Aleutian Islands, Alaska · 50 km SW of this epicentre Jan 1, 1902
2. 6.5 127 km E of Nikolski, Alaska · 11 km NW of this epicentre Oct 13, 2009
3. 6.4 118 km E of Nikolski, Alaska · 18 km WNW of this epicentre Mar 15, 1957
4. 6.4 123 km ESE of Nikolski, Alaska · 17 km WSW of this epicentre Oct 13, 2009
5. 6.3 136 km ESE of Nikolski, Alaska · 4 km S of this epicentre Jan 12, 1952

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 52.6776, -166.8982. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.6 112 km E of Nikolski, Alaska 10:58 UTC
2. 2.9 Fox Islands, Aleutian Islands, Alaska 15:51 UTC
3. 2.6 Fox Islands, Aleutian Islands, Alaska 16:37 UTC
4. 1.5 96 km E of Nikolski, Alaska 06:51 UTC
5. 1.5 95 km E of Nikolski, Alaska 06:49 UTC
6. 2.0 95 km E of Nikolski, Alaska 06:47 UTC
7. 1.6 100 km E of Nikolski, Alaska 06:45 UTC
8. 3.2 95 km E of Nikolski, Alaska 05:57 UTC
9. 1.7 Fox Islands, Aleutian Islands, Alaska 01:21 UTC
10. 1.7 99 km E of Nikolski, Alaska 01:20 UTC
11. 2.5 118 km ESE of Nikolski, Alaska 18:23 UTC
12. 2.0 129 km ESE of Nikolski, Alaska 20:39 UTC
13. 3.0 Fox Islands, Aleutian Islands, Alaska 00:46 UTC
14. 2.8 85 km S of Unalaska, Alaska 09:41 UTC
15. 1.6 98 km E of Nikolski, Alaska 08:48 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:06 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.