94 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, people at rest would likely notice it out to about 9 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 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 22 earthquakes of M5 or more within 50 km; the five largest:

1. 7.4 54 km SE of Sand Point, Alaska · 42 km NNW of this epicentre May 31, 1917
2. 6.6 72 km SE of Sand Point, Alaska · 33 km N of this epicentre Oct 16, 1932
3. 6.6 85 km SE of Sand Point, Alaska · 14 km N of this epicentre Oct 9, 1985
4. 6.5 94 km ESE of Sand Point, Alaska · 44 km NE of this epicentre Feb 14, 1983
5. 6.3 68 km SE of Sand Point, Alaska · 37 km N of this epicentre Oct 30, 1932

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 54.6376, -159.6499. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.8 110 km SSE of Sand Point, Alaska 02:46 UTC
2. 2.9 99 km SSE of Sand Point, Alaska 02:41 UTC
3. 1.7 south of Alaska 02:22 UTC
4. 1.8 126 km SSE of Sand Point, Alaska 02:17 UTC
5. 2.0 111 km SSE of Sand Point, Alaska 02:09 UTC
6. 1.8 111 km SSE of Sand Point, Alaska 02:04 UTC
7. 1.8 128 km SSE of Sand Point, Alaska 02:00 UTC
8. 2.7 125 km SSE of Sand Point, Alaska 01:56 UTC
9. 1.6 107 km SSE of Sand Point, Alaska 01:52 UTC
10. 2.0 104 km SSE of Sand Point, Alaska 01:50 UTC
11. 3.6 112 km SSE of Sand Point, Alaska 01:47 UTC
12. 2.1 105 km SSE of Sand Point, Alaska 01:47 UTC
13. 1.7 83 km SSE of Sand Point, Alaska 01:44 UTC
14. 1.8 95 km SSE of Sand Point, Alaska 01:43 UTC
15. 1.6 100 km SSE of Sand Point, Alaska 01:41 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 23:02 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.