148 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 82 km (51 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 7.6 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.8 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 22,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 1,000× the energy of this one
3. Magna, Utah 2020 M 5.7 710× the energy of this one
4. This earthquake M 3.8 about 7.6 tons of TNT
5. Around the size people start to feel M 3.0 this one released 16× 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.

For this area

The largest earthquake within 50 km since 2016 was M 5.9 on 2020-10-19 — about 1,400 times the energy of this one.

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

1. 5.9 131 km S of Sand Point, Alaska · 49 km W of this epicentre Dec 3, 1933
2. 5.0 188 km SSE of Sand Point, Alaska · 48 km SSW of this epicentre Oct 16, 2001

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 54.0927, -159.6494. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.9 138 km SSE of Sand Point, Alaska 01:35 UTC
2. 2.3 102 km SSE of Sand Point, Alaska 01:33 UTC
3. 2.8 123 km SSE of Sand Point, Alaska 01:24 UTC
4. 2.8 101 km SSE of Sand Point, AK 01:22 UTC
5. 5.1 130 km SSE of Sand Point, Alaska 01:17 UTC
6. 2.6 106 km SSE of Sand Point, Alaska 01:03 UTC
7. 3.8 125 km SSE of Sand Point, Alaska 00:57 UTC
8. 3.2 125 km SSE of Sand Point, Alaska 00:57 UTC
9. 2.8 113 km SSE of Sand Point, Alaska 00:52 UTC
10. 2.3 110 km SSE of Sand Point, Alaska 00:50 UTC
11. 3.0 107 km SSE of Sand Point, Alaska 00:46 UTC
12. 4.3 111 km SSE of Sand Point, Alaska 00:35 UTC
13. 2.9 127 km SSE of Sand Point, Alaska 00:29 UTC
14. 3.0 133 km SSE of Sand Point, Alaska 00:21 UTC
15. 2.9 114 km SE of Sand Point, Alaska 00:07 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 17:13 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.