152 km E 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 9 km (6 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 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
3. Around the size people start to feel M 3.0 63× the energy of this one
4. This earthquake M 1.8 about 15 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 45,000 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 · 46 km WSW of this epicentre Jul 7, 1920
2. 5.7 152 km E of McCarthy, Alaska · 4 km S of this epicentre Jun 26, 2001
3. 5.4 140 km SSE of Alcan Border, Alaska · 15 km NW of this epicentre Jun 10, 1972
4. 5.4 136 km SSE of Alcan Border, Alaska · 19 km N of this epicentre Mar 30, 1983
5. 5.3 136 km E of McCarthy, Alaska · 17 km WNW 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 61.3790, -140.0774. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.2 123 km E of McCarthy, Alaska 12:33 UTC
2. 1.9 132 km ESE of McCarthy, Alaska 10:55 UTC
3. 1.8 132 km ESE of McCarthy, Alaska 09:03 UTC
4. 2.2 129 km ESE of McCarthy, Alaska 00:05 UTC
5. 1.5 153 km E of McCarthy, Alaska 02:46 UTC
6. 1.5 131 km E of McCarthy, Alaska 07:34 UTC
7. 1.5 134 km ESE of McCarthy, Alaska 19:22 UTC
8. 1.8 156 km N of Yakutat, Alaska 14:33 UTC
9. 1.9 127 km ESE of McCarthy, Alaska 13:28 UTC
10. 1.6 165 km SSE of Alcan Border, Alaska 01:40 UTC
11. 1.6 156 km ESE of McCarthy, Alaska 21:03 UTC
12. 2.1 154 km ESE of McCarthy, Alaska 20:24 UTC
13. 2.4 135 km E of McCarthy, Alaska 22:54 UTC
14. 2.8 125 km E of McCarthy, Alaska 19:16 UTC
15. 3.3 124 km E of McCarthy, Alaska 19:15 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 14:35 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.