98 km SE of Ugashik, Alaska

This was a minor earthquake. Quakes this small are rarely felt and do not cause 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 30 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 500,000× the energy of this one
2. Magna, Utah 2020 M 5.7 350,000× the energy of this one
3. Around the size people start to feel M 3.0 32× the energy of this one
4. This earthquake M 2.0 about 30 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 4.5 on 2016-02-14 — about 5,600 times the energy of this one.

Before 2016, the USGS record lists 9 earthquakes of M5 or more within 50 km; the five largest:

1. 6.8 117 km SSE of Ugashik, Alaska · 31 km SSW of this epicentre May 29, 2015
2. 6.4 104 km SSE of Ugashik, Alaska · 36 km SW of this epicentre May 20, 1979
3. 5.4 115 km SSE of Ugashik, Alaska · 25 km S of this epicentre Jun 9, 1971
4. 5.4 113 km SSE of Ugashik, Alaska · 30 km SSW of this epicentre Jan 27, 2004
5. 5.3 117 km SSE of Ugashik, Alaska · 34 km SSW of this epicentre Dec 28, 1985

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 56.8660, -156.2973. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.2 123 km E of Chignik, Alaska 21:39 UTC
2. 1.5 100 km ESE of Ugashik, Alaska 15:24 UTC
3. 1.6 70 km ESE of Ugashik, Alaska 03:04 UTC
4. 1.5 67 km ESE of Ugashik, Alaska 15:54 UTC
5. 2.1 128 km WSW of Akhiok, Alaska 14:28 UTC
6. 2.0 124 km SSE of Ugashik, Alaska 07:18 UTC
7. 2.6 Alaska Peninsula 04:42 UTC
8. 2.5 97 km ESE of Ugashik, Alaska 08:50 UTC
9. 2.0 103 km W of Akhiok, Alaska 23:47 UTC
10. 2.4 114 km SSE of Ugashik, Alaska 13:40 UTC
11. 2.7 80 km ESE of Ugashik, Alaska 10:23 UTC
12. 2.0 88 km SE of Ugashik, Alaska 05:55 UTC
13. 2.3 53 km SE of Ugashik, Alaska 01:03 UTC
14. 2.8 Alaska Peninsula 15:10 UTC
15. 2.7 124 km WSW of Akhiok, Alaska 18:41 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 17:34 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.