91 km SSE of Sand Point, Alaska

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 8 km (5 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 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
3. Around the size people start to feel M 3.0 11× the energy of this one
4. This earthquake M 2.3 about 85 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 89,000,000 times the energy of this one.

Before 2016, the USGS record lists 19 earthquakes of M5 or more within 50 km; the five largest:

1. 7.4 54 km SE of Sand Point, Alaska · 43 km N of this epicentre May 31, 1917
2. 6.6 72 km SE of Sand Point, Alaska · 38 km NNE of this epicentre Oct 16, 1932
3. 6.6 85 km SE of Sand Point, Alaska · 22 km NE of this epicentre Oct 9, 1985
4. 6.3 68 km SE of Sand Point, Alaska · 42 km NNE of this epicentre Oct 30, 1932
5. 6.1 79 km SE of Sand Point, Alaska · 17 km N 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 54.6092, -159.8310. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.3 58 km SE of Sand Point, Alaska 03:30 UTC
2. 2.3 101 km SSE of Sand Point, Alaska 22:32 UTC
3. 2.3 95 km SSE of Sand Point, Alaska 07:29 UTC
4. 2.2 101 km SSE of Sand Point, Alaska 04:32 UTC
5. 2.2 100 km SSE of Sand Point, Alaska 19:58 UTC
6. 2.6 81 km SE of Sand Point, Alaska 08:30 UTC
7. 2.4 96 km SSE of Sand Point, Alaska 13:04 UTC
8. 2.6 105 km SSE of Sand Point, Alaska 23:44 UTC
9. 2.5 106 km SSE of Sand Point, Alaska 20:27 UTC
10. 2.9 93 km SSE of Sand Point, Alaska 10:45 UTC
11. 2.1 100 km SSE of Sand Point, Alaska 19:28 UTC
12. 3.1 137 km SSE of Sand Point, Alaska 18:26 UTC
13. 3.2 107 km SSE of Sand Point, Alaska 06:04 UTC
14. 1.9 93 km SSE of Sand Point, Alaska 22:16 UTC
15. 2.7 130 km SSE of Sand Point, Alaska 06:53 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 20:32 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.