103 km E 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 4 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 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
3. Around the size people start to feel M 3.0 130× the energy of this one
4. This earthquake M 1.6 about 7.6 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 6.9 on 2021-10-11 — about 89,000,000 times the energy of this one.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

1. 6.8 117 km SSE of Ugashik, Alaska · 30 km NE of this epicentre May 29, 2015
2. 6.5 60 km ENE of Chignik, Alaska · 49 km WNW of this epicentre Sep 28, 1941
3. 6.4 77 km ESE of Chignik, Alaska · 39 km SW of this epicentre Mar 24, 1972
4. 6.4 104 km SSE of Ugashik, Alaska · 30 km N of this epicentre May 20, 1979
5. 6.3 112 km E of Chignik, Alaska · 23 km SSE of this epicentre Feb 25, 1953

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 56.3816, -156.7403. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.7 97 km E of Chignik, Alaska 13:47 UTC
2. 1.6 121 km SSE of Ugashik, Alaska 11:34 UTC
3. 2.0 91 km ENE of Chignik, Alaska 11:00 UTC
4. 2.5 114 km E of Chignik, Alaska 01:57 UTC
5. 2.4 114 km E of Chignik, Alaska 03:52 UTC
6. 1.8 91 km E of Chignik, Alaska 12:14 UTC
7. 1.8 95 km SSE of Ugashik, Alaska 14:19 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. 3.0 125 km SSE of Ugashik, Alaska 05:54 UTC
12. 1.8 102 km E of Chignik, Alaska 01:47 UTC
13. 1.9 102 km E of Chignik, Alaska 08:26 UTC
14. 1.9 100 km E of Chignik, Alaska 08:09 UTC
15. 2.0 116 km E of Chignik, Alaska 08:06 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 20:41 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.