Alaska Peninsula

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 10 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 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 in our catalogue was M 4.0 on 2016-12-16 — about 2,800 times the energy of this one.

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 56.5112, -157.2203. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.8 96 km ENE of Chignik, Alaska 21:55 UTC
2. 2.1 105 km SSE of Ugashik, Alaska 01:53 UTC
3. 1.7 97 km E of Chignik, Alaska 13:47 UTC
4. 1.8 72 km S of Ugashik, Alaska 02:07 UTC
5. 2.0 91 km ENE of Chignik, Alaska 11:00 UTC
6. 1.8 91 km E of Chignik, Alaska 12:14 UTC
7. 2.9 64 km ESE of Port Heiden, Alaska 21:16 UTC
8. 2.3 98 km E of Chignik, Alaska 14:04 UTC
9. 2.0 97 km E of Chignik, Alaska 11:26 UTC
10. 1.8 101 km E of Chignik, Alaska 11:08 UTC
11. 1.8 102 km E of Chignik, Alaska 01:47 UTC
12. 1.9 102 km E of Chignik, Alaska 08:26 UTC
13. 1.9 100 km E of Chignik, Alaska 08:09 UTC
14. 2.0 100 km E of Chignik, Alaska 06:15 UTC
15. 2.5 95 km E of Chignik, Alaska 22:05 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 20:16 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.