69 km SSW 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 7 km (4 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 4.3 on 2020-08-09 — about 5,600 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

1. 5.7 84 km SSW of McCarthy, Alaska · 16 km SW of this epicentre May 8, 1964
2. 5.2 84 km SSW of McCarthy, Alaska · 17 km WSW of this epicentre May 17, 1967
3. 5.2 90 km SSW of McCarthy, Alaska · 22 km SW of this epicentre Oct 8, 2008

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 60.8587, -143.4436. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.4 106 km S of McCarthy, Alaska 18:54 UTC
2. 1.5 87 km S of McCarthy, Alaska 22:16 UTC
3. 2.1 107 km S of McCarthy, Alaska 01:39 UTC
4. 2.3 65 km SSE of Chitina, Alaska 06:38 UTC
5. 1.6 94 km S of McCarthy, Alaska 09:18 UTC
6. 2.3 104 km S of McCarthy, Alaska 14:54 UTC
7. 1.5 110 km E of Cordova, Alaska 13:58 UTC
8. 2.1 104 km S of McCarthy, Alaska 01:37 UTC
9. 3.1 116 km SSW of McCarthy, Alaska 16:54 UTC
10. 2.7 105 km S of McCarthy, Alaska 18:31 UTC
11. 2.2 114 km E of Cordova, Alaska 08:09 UTC
12. 1.6 112 km S of McCarthy, Alaska 21:00 UTC
13. 2.5 113 km SSW of McCarthy, Alaska 05:02 UTC
14. 2.5 109 km S of McCarthy, Alaska 10:10 UTC
15. 1.5 110 km S of McCarthy, Alaska 08:30 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 16:01 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.