137 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 11 km (7 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 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
2. Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
3. Around the size people start to feel M 3.0 89× the energy of this one
4. This earthquake M 1.7 about 11 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 63,000 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

1. 6.1 109 km E of McCarthy, Alaska · 29 km WNW of this epicentre Jul 7, 1920
2. 5.7 152 km E of McCarthy, Alaska · 32 km NE of this epicentre Jun 26, 2001
3. 5.4 140 km SSE of Alcan Border, Alaska · 42 km NNE of this epicentre Jun 10, 1972
4. 5.3 136 km E of McCarthy, Alaska · 36 km N of this epicentre Apr 29, 2004
5. 5.1 145 km ESE of McCarthy, Alaska · 12 km NE of this epicentre Jun 5, 2014

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 61.1190, -140.4440. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.6 157 km ESE of McCarthy, Alaska 20:24 UTC
2. 1.8 160 km E of McCarthy, Alaska 20:26 UTC
3. 1.8 146 km NNW of Yakutat, Alaska 10:24 UTC
4. 1.6 152 km E of McCarthy, Alaska 11:56 UTC
5. 1.6 159 km ESE of McCarthy, Alaska 20:18 UTC
6. 1.6 152 km SSE of Alcan Border, Alaska 15:53 UTC
7. 1.6 158 km ESE of McCarthy, Alaska 09:16 UTC
8. 1.7 123 km E of McCarthy, Alaska 18:40 UTC
9. 2.4 115 km ESE of McCarthy, Alaska 19:31 UTC
10. 2.3 114 km ESE of McCarthy, Alaska 19:30 UTC
11. 1.5 156 km ESE of McCarthy, Alaska 21:22 UTC
12. 2.4 123 km E of McCarthy, Alaska 18:02 UTC
13. 1.8 124 km E of McCarthy, Alaska 18:00 UTC
14. 1.7 123 km E of McCarthy, Alaska 16:01 UTC
15. 1.6 122 km ESE of McCarthy, Alaska 19:08 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 15:44 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.