86 km ENE of Chignik, 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 1.9 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 89,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 4,000× the energy of this one
3. Magna, Utah 2020 M 5.7 2,800× the energy of this one
4. This earthquake M 3.4 about 1.9 tons of TNT
5. Around the size people start to feel M 3.0 this one released 4× 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 4.0 on 2016-12-16 — about 7.9 times the energy of this one.

Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:

1. 6.8 117 km SSE of Ugashik, Alaska · 45 km E of this epicentre May 29, 2015
2. 6.5 60 km ENE of Chignik, Alaska · 27 km SW of this epicentre Sep 28, 1941
3. 6.4 61 km ENE of Chignik, Alaska · 25 km WSW of this epicentre Jan 1, 1963
4. 6.4 104 km SSE of Ugashik, Alaska · 27 km E of this epicentre May 20, 1979
5. 5.7 71 km ENE of Chignik, Alaska · 18 km SSW of this epicentre Feb 7, 1967

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 56.6560, -157.1640. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.3 81 km ENE of Chignik, Alaska 22:35 UTC
2. 2.4 68 km S of Ugashik, Alaska 12:38 UTC
3. 2.0 51 km SSE of Ugashik, Alaska 08:24 UTC
4. 2.5 102 km ENE of Chignik, Alaska 06:30 UTC
5. 2.5 103 km ENE of Chignik, Alaska 15:23 UTC
6. 3.1 51 km E of Chignik, Alaska 00:34 UTC
7. 2.3 61 km SSE of Ugashik, Alaska 01:50 UTC
8. 2.6 79 km E of Chignik, Alaska 06:42 UTC
9. 2.1 100 km ENE of Chignik, Alaska 05:37 UTC
10. 1.7 69 km S of Ugashik, Alaska 13:47 UTC
11. 2.2 96 km SSE of Ugashik, Alaska 08:14 UTC
12. 1.9 59 km SSW of Ugashik, Alaska 15:05 UTC
13. 3.0 79 km E of Chignik, Alaska 22:15 UTC
14. 2.2 107 km E of Chignik, Alaska 04:02 UTC
15. 2.2 60 km NE of Chignik, Alaska 23:47 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 09:10 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.