2020 Sand Point, Alaska Earthquake

This was a major earthquake. Serious damage is likely near the epicentre. Follow official information from USGS and local authorities. 321 people have reported feeling it to USGS.

How big was it?

This earthquake released about 3.8 megatons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 8.6 would have released about 32 times as much.

1. Great Alaska earthquake 1964 M 9.2 250× the energy of this one
2. Tōhoku, Japan 2011 M 9.1 180× the energy of this one
3. San Francisco 1906 M 7.9 2.8× the energy of this one
4. This earthquake M 7.6 about 3.8 megatons of TNT
5. Ridgecrest, California 2019 M 7.1 this one released 5.6× more
6. Loma Prieta, California 1989 M 6.9 this one released 11× more

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 54.6020, -159.6258. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.7 113 km SSE of Sand Point, Alaska 23:11 UTC
2. 2.6 94 km SSE of Sand Point, Alaska 23:11 UTC
3. 3.5 104 km SSE of Sand Point, Alaska 23:09 UTC
4. 3.2 85 km SE of Sand Point, Alaska 23:07 UTC
5. 4.2 100 km SSE of Sand Point, Alaska 23:04 UTC
6. 2.7 85 km SE of Sand Point, Alaska 23:01 UTC
7. 3.2 123 km SSE of Sand Point, Alaska 23:00 UTC
8. 2.9 107 km SSE of Sand Point, Alaska 22:58 UTC
9. 3.2 95 km SSE of Sand Point, Alaska 22:57 UTC
10. 3.1 89 km SSE of Sand Point, Alaska 22:56 UTC
11. 3.7 116 km SSE of Sand Point, Alaska 22:52 UTC
12. 4.0 132 km SSE of Sand Point, Alaska 22:51 UTC
13. 3.7 100 km SSE of Sand Point, Alaska 22:50 UTC
14. 3.1 93 km SE of Sand Point, Alaska 22:49 UTC
15. 3.5 125 km SSE of Sand Point, Alaska 22:47 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 06:58 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 5.9 on 2020-10-06.

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.