121 km ESE of Sand Point, Alaska

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

How big was it?

This earthquake released about 950 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 350,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 16,000× the energy of this one
3. Magna, Utah 2020 M 5.7 11,000× the energy of this one
4. This earthquake M 3.0 about 950 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.

Where

Epicentre 54.7767, -158.8599. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.3 78 km ESE of Sand Point, Alaska 02:20 UTC
2. 3.0 135 km SSE of Perryville, Alaska 09:51 UTC
3. 2.0 82 km ESE of Sand Point, Alaska 21:21 UTC
4. 1.9 80 km ESE of Sand Point, Alaska 03:02 UTC
5. 2.0 99 km SSE of Perryville, Alaska 02:51 UTC
6. 3.1 121 km SSE of Perryville, Alaska 06:08 UTC
7. 1.6 83 km ESE of Sand Point, Alaska 07:45 UTC
8. 2.0 97 km SSE of Perryville, Alaska 14:32 UTC
9. 2.0 102 km SSE of Perryville, Alaska 21:03 UTC
10. 2.1 90 km SSE of Perryville, Alaska 17:23 UTC
11. 2.1 90 km ESE of Sand Point, Alaska 12:35 UTC
12. 1.5 125 km SE of Sand Point, Alaska 13:56 UTC
13. 2.1 144 km ESE of Sand Point, Alaska 10:54 UTC
14. 2.7 134 km ESE of Sand Point, Alaska 08:34 UTC
15. 1.7 78 km ESE of Sand Point, Alaska 08:31 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 17:49 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 7.8 on 2020-07-22 — it released about 16,000,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

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.