136 km E of McCarthy, 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 42 km (26 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 250,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
4. This earthquake M 3.1 about 1,300 lb of TNT
5. Around the size people start to feel M 3.0 this one released 1.4× 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 4.9 on 2021-05-09 — about 500 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 · 36 km SW of this epicentre Jul 7, 1920
2. 5.7 152 km E of McCarthy, Alaska · 21 km SE of this epicentre Jun 26, 2001
3. 5.4 140 km SSE of Alcan Border, Alaska · 6 km ENE of this epicentre Jun 10, 1972
4. 5.4 136 km SSE of Alcan Border, Alaska · 17 km ENE of this epicentre Mar 30, 1983
5. 5.3 136 km E of McCarthy, Alaska · 2 km S 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 61.4620, -140.3653. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.5 141 km WNW of Haines Junction, Canada 12:24 UTC
2. 1.5 140 km WNW of Haines Junction, Canada 12:23 UTC
3. 1.6 117 km E of McCarthy, Alaska 09:33 UTC
4. 2.1 131 km ESE of McCarthy, Alaska 18:22 UTC
5. 1.8 152 km WNW of Haines Junction, Canada 06:17 UTC
6. 1.8 121 km ESE of McCarthy, Alaska 09:46 UTC
7. 2.5 121 km E of McCarthy, Alaska 08:50 UTC
8. 1.9 123 km E of McCarthy, Alaska 04:58 UTC
9. 1.6 144 km WNW of Haines Junction, Canada 00:08 UTC
10. 1.6 122 km E of McCarthy, Alaska 15:48 UTC
11. 1.5 136 km E of McCarthy, Alaska 13:29 UTC
12. 1.6 121 km E of McCarthy, Alaska 05:40 UTC
13. 1.5 119 km E of McCarthy, Alaska 16:16 UTC
14. 1.6 143 km E of McCarthy, Alaska 06:12 UTC
15. 2.8 126 km E of McCarthy, Alaska 06:00 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 04:04 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.