94 km SSE of False Pass, 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 2 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 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
3. Around the size people start to feel M 3.0 22× the energy of this one
4. This earthquake M 2.1 about 43 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 5.1 on 2019-02-15 — about 32,000 times the energy of this one.

Before 2016, the USGS record lists 33 earthquakes of M5 or more within 50 km; the five largest:

1. 6.5 88 km SE of False Pass, Alaska · 35 km NE of this epicentre Jun 21, 1987
2. 6.0 129 km S of False Pass, Alaska · 44 km SSW of this epicentre Jan 14, 1961
3. 6.0 96 km SSW of False Pass, Alaska · 47 km W of this epicentre May 29, 1973
4. 6.0 137 km S of False Pass, Alaska · 48 km SSW of this epicentre May 22, 1988
5. 5.8 112 km SE of False Pass, Alaska · 43 km E of this epicentre Feb 24, 1939

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 54.0288, -163.0469. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.8 94 km S of False Pass, Alaska 16:33 UTC
2. 4.2 105 km S of False Pass, Alaska 16:19 UTC
3. 2.0 78 km SE of False Pass, Alaska 16:20 UTC
4. 2.1 85 km SE of False Pass, Alaska 23:51 UTC
5. 2.7 83 km S of False Pass, Alaska 12:29 UTC
6. 3.8 121 km SSE of False Pass, Alaska 08:37 UTC
7. 2.7 122 km SSE of False Pass, Alaska 20:42 UTC
8. 2.9 83 km S of False Pass, Alaska 04:20 UTC
9. 1.9 94 km S of False Pass, Alaska 13:41 UTC
10. 2.7 125 km S of False Pass, Alaska 16:46 UTC
11. 2.5 84 km SSE of False Pass, Alaska 18:14 UTC
12. 2.3 80 km S of False Pass, Alaska 03:11 UTC
13. 2.7 97 km S of False Pass, Alaska 15:10 UTC
14. 2.8 92 km SE of False Pass, Alaska 19:08 UTC
15. 3.2 117 km S of False Pass, Alaska 10:46 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 06:37 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.