119 km SSE of Ugashik, 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 240 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 63,000× the energy of this one
2. Magna, Utah 2020 M 5.7 45,000× the energy of this one
3. Around the size people start to feel M 3.0 4× the energy of this one
4. This earthquake M 2.6 about 240 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 2017-03-28 — about 710 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 · 7 km WSW of this epicentre May 29, 2015
2. 6.4 104 km SSE of Ugashik, Alaska · 25 km W of this epicentre May 20, 1979
3. 6.1 132 km E of Chignik, Alaska · 47 km S of this epicentre Sep 13, 1911
4. 5.4 115 km SSE of Ugashik, Alaska · 4 km NW of this epicentre Jun 9, 1971
5. 5.4 113 km SSE of Ugashik, Alaska · 10 km W of this epicentre Jan 27, 2004

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 56.6162, -156.3240. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.0 114 km SSE of Ugashik, Alaska 00:59 UTC
2. 2.3 Alaska Peninsula 00:44 UTC
3. 2.5 104 km SSE of Ugashik, Alaska 20:08 UTC
4. 2.3 124 km E of Chignik, Alaska 16:05 UTC
5. 2.1 118 km E of Chignik, Alaska 03:08 UTC
6. 2.3 120 km SW of Akhiok, Alaska 05:12 UTC
7. 3.3 114 km E of Chignik, Alaska 16:57 UTC
8. 3.5 113 km E of Chignik, Alaska 01:40 UTC
9. 3.2 138 km WSW of Akhiok, Alaska 18:30 UTC
10. 2.2 110 km WSW of Akhiok, Alaska 20:09 UTC
11. 2.0 112 km W of Akhiok, Alaska 15:10 UTC
12. 2.9 137 km WSW of Akhiok, Alaska 00:53 UTC
13. 2.1 114 km ENE of Chignik, Alaska 18:23 UTC
14. 2.4 128 km E of Chignik, Alaska 23:09 UTC
15. 1.8 88 km SE of Ugashik, Alaska 14:13 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 02:27 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.