115 km SSE 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 7 km (4 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 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
3. Around the size people start to feel M 3.0 5.6× the energy of this one
4. This earthquake M 2.5 about 170 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 45,000,000 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

1. 6.6 85 km SE of Sand Point, Alaska · 42 km NNE of this epicentre Oct 9, 1985
2. 6.1 79 km SE of Sand Point, Alaska · 40 km N of this epicentre Nov 14, 1985
3. 6.0 71 km SSE of Sand Point, Alaska · 44 km NNW of this epicentre Jun 27, 1918
4. 5.9 113 km SE of Sand Point, Alaska · 41 km NE of this epicentre Jun 7, 1917
5. 5.9 99 km SE of Sand Point, Alaska · 30 km NNE of this epicentre Oct 20, 1929

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 54.3984, -159.7424. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.0 105 km SSE of Sand Point, Alaska 08:45 UTC
2. 2.2 105 km SSE of Sand Point, Alaska 04:59 UTC
3. 2.5 114 km SSE of Sand Point, Alaska 07:07 UTC
4. 2.0 98 km SSE of Sand Point, Alaska 17:16 UTC
5. 3.5 105 km SSE of Sand Point, Alaska 03:15 UTC
6. 1.6 94 km SE of Sand Point, Alaska 03:25 UTC
7. 3.3 93 km SE of Sand Point, Alaska 10:04 UTC
8. 1.6 99 km SE of Sand Point, Alaska 09:54 UTC
9. 1.8 103 km SSE of Sand Point, Alaska 06:45 UTC
10. 1.7 106 km SSE of Sand Point, Alaska 03:56 UTC
11. 1.5 92 km SSE of Sand Point, Alaska 00:48 UTC
12. 1.8 123 km SSE of Sand Point, Alaska 19:24 UTC
13. 2.0 120 km SSE of Sand Point, Alaska 11:19 UTC
14. 2.1 99 km SSE of Sand Point, Alaska 06:55 UTC
15. 2.0 116 km SSE of Sand Point, Alaska 12:45 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 21:57 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.