113 km SE of Sand Point, 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 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
3. Around the size people start to feel M 3.0 2× the energy of this one
4. This earthquake M 2.8 about 480 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 7.6 on 2020-10-19 — about 16,000,000 times the energy of this one.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

1. 6.6 72 km SE of Sand Point, Alaska · 43 km NNW of this epicentre Oct 16, 1932
2. 6.6 85 km SE of Sand Point, Alaska · 28 km NW of this epicentre Oct 9, 1985
3. 6.5 94 km ESE of Sand Point, Alaska · 40 km N of this epicentre Feb 14, 1983
4. 6.3 68 km SE of Sand Point, Alaska · 48 km NNW of this epicentre Oct 30, 1932
5. 6.1 79 km SE of Sand Point, Alaska · 36 km WNW of this epicentre Nov 14, 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 54.5824, -159.3083. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.7 111 km SSE of Sand Point, Alaska 08:38 UTC
2. 1.8 104 km SSE of Sand Point, Alaska 07:11 UTC
3. 1.8 103 km SSE of Sand Point, Alaska 05:14 UTC
4. 1.6 99 km SSE of Sand Point, Alaska 03:05 UTC
5. 2.8 104 km SSE of Sand Point, Alaska 02:39 UTC
6. 1.6 72 km ESE of Sand Point, Alaska 02:11 UTC
7. 2.9 105 km SSE of Sand Point, Alaska 20:43 UTC
8. 2.5 103 km SSE of Sand Point, Alaska 16:27 UTC
9. 2.2 122 km SSE of Sand Point, Alaska 01:58 UTC
10. 2.0 111 km SSE of Sand Point, Alaska 01:51 UTC
11. 1.9 106 km SSE of Sand Point, Alaska 00:26 UTC
12. 1.8 114 km SSE of Sand Point, Alaska 23:57 UTC
13. 1.6 90 km SSE of Sand Point, Alaska 10:00 UTC
14. 1.9 south of Alaska 05:41 UTC
15. 1.9 105 km SE of Sand Point, Alaska 16:36 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 23:46 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.