125 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 1 km (1 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 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
3. Around the size people start to feel M 3.0 63× the energy of this one
4. This earthquake M 1.8 about 15 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 500,000,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

1. 5.9 99 km SE of Sand Point, Alaska · 49 km NNE of this epicentre Oct 20, 1929
2. 5.9 131 km S of Sand Point, Alaska · 33 km WSW of this epicentre Dec 3, 1933

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 54.2574, -159.9215. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.9 93 km SSE of Sand Point, Alaska 01:36 UTC
2. 2.3 109 km SE of Sand Point, Alaska 23:05 UTC
3. 2.3 98 km SSE of Sand Point, Alaska 20:00 UTC
4. 1.6 south of Alaska 19:21 UTC
5. 1.6 102 km SSE of Sand Point, Alaska 19:20 UTC
6. 2.1 87 km SSE of Sand Point, Alaska 19:03 UTC
7. 2.9 119 km SSE of Sand Point, Alaska 05:14 UTC
8. 2.3 100 km SSE of Sand Point, Alaska 21:09 UTC
9. 2.5 111 km SSE of Sand Point, Alaska 20:41 UTC
10. 2.3 104 km SSE of Sand Point, Alaska 20:32 UTC
11. 3.0 113 km SE of Sand Point, Alaska 10:08 UTC
12. 1.8 88 km SSE of Sand Point, Alaska 15:42 UTC
13. 1.9 95 km SSE of Sand Point, Alaska 04:15 UTC
14. 1.6 112 km SSE of Sand Point, Alaska 04:04 UTC
15. 1.5 100 km SE of Sand Point, Alaska 03:55 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 20:24 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.