61 km ESE of Chignik, 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 3 km (2 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 5.7 on 2021-07-29 — about 1,000,000 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

1. 6.5 60 km ENE of Chignik, Alaska · 50 km N of this epicentre Sep 28, 1941
2. 6.4 77 km ESE of Chignik, Alaska · 22 km ENE of this epicentre Mar 24, 1972
3. 5.5 51 km SSE of Chignik, Alaska · 50 km WSW of this epicentre Feb 24, 1972
4. 5.1 85 km ESE of Chignik, Alaska · 26 km E of this epicentre Jan 7, 2006

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 56.0532, -157.5072. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.4 70 km ENE of Chignik, Alaska 10:09 UTC
2. 2.2 53 km E of Chignik, Alaska 23:23 UTC
3. 2.2 100 km SE of Chignik, Alaska 05:04 UTC
4. 2.0 65 km ESE of Chignik, Alaska 08:51 UTC
5. 1.8 47 km E of Chignik, Alaska 03:12 UTC
6. 2.2 80 km E of Chignik, Alaska 21:22 UTC
7. 2.0 40 km E of Chignik, Alaska 15:45 UTC
8. 2.1 44 km ESE of Chignik, Alaska 06:55 UTC
9. 2.3 48 km E of Chignik, Alaska 10:42 UTC
10. 1.7 39 km SE of Chignik, Alaska 21:14 UTC
11. 1.8 76 km ESE of Chignik, Alaska 15:10 UTC
12. 2.4 55 km E of Chignik, Alaska 04:18 UTC
13. 2.6 45 km E of Chignik, Alaska 00:14 UTC
14. 1.9 28 km ESE of Chignik, Alaska 23:54 UTC
15. 1.8 101 km SE of Chignik, Alaska 01:32 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 06:25 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.