150 km ESE of McCarthy, 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 8 km (5 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 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
3. Around the size people start to feel M 3.0 180× the energy of this one
4. This earthquake M 1.5 about 5.4 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 4.9 on 2021-05-09 — about 130,000 times the energy of this one.

Before 2016, the USGS record lists 9 earthquakes of M5 or more within 50 km; the five largest:

1. 6.1 109 km E of McCarthy, Alaska · 40 km WNW of this epicentre Jul 7, 1920
2. 5.7 152 km E of McCarthy, Alaska · 19 km NNE of this epicentre Jun 26, 2001
3. 5.4 140 km SSE of Alcan Border, Alaska · 35 km N of this epicentre Jun 10, 1972
4. 5.4 136 km SSE of Alcan Border, Alaska · 42 km N of this epicentre Mar 30, 1983
5. 5.3 136 km E of McCarthy, Alaska · 32 km NNW of this epicentre Apr 29, 2004

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 61.1740, -140.1668. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.0 150 km ESE of McCarthy, Alaska 22:02 UTC
2. 1.7 152 km ESE of McCarthy, Alaska 20:59 UTC
3. 1.8 152 km ESE of McCarthy, Alaska 20:27 UTC
4. 2.7 135 km N of Yakutat, Alaska 04:20 UTC
5. 1.7 146 km ESE of McCarthy, Alaska 03:28 UTC
6. 1.8 128 km ESE of McCarthy, Alaska 21:05 UTC
7. 2.1 154 km N of Yakutat, Alaska 19:14 UTC
8. 1.7 143 km ESE of McCarthy, Alaska 18:12 UTC
9. 2.0 134 km N of Yakutat, Alaska 20:06 UTC
10. 2.2 138 km N of Yakutat, Alaska 04:13 UTC
11. 1.9 133 km ESE of McCarthy, Alaska 11:34 UTC
12. 2.3 136 km N of Yakutat, Alaska 08:45 UTC
13. 2.6 137 km N of Yakutat, Alaska 07:26 UTC
14. 3.5 139 km N of Yakutat, Alaska 07:02 UTC
15. 2.3 133 km N of Yakutat, Alaska 06:48 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 23:15 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.