30 km SSE of Nelchina, 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 8 km (5 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 30 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 500,000× the energy of this one
2. Magna, Utah 2020 M 5.7 350,000× the energy of this one
3. Around the size people start to feel M 3.0 32× the energy of this one
4. This earthquake M 2.0 about 30 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 2018-10-16 — about 2,800 times the energy of this one.

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

1. 5.1 48 km NNW of Valdez, Alaska · 26 km SSW of this epicentre Mar 28, 1964
2. 5.1 9 km ESE of Eureka Roadhouse, Alaska · 33 km WNW of this epicentre May 13, 1993
3. 5.1 48 km SSE of Nelchina, Alaska · 19 km S of this epicentre Aug 25, 2004

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 61.7559, -146.4595. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.5 47 km SSE of Nelchina, Alaska 06:49 UTC
2. 1.5 36 km N of Valdez, Alaska 16:58 UTC
3. 1.5 19 km SSE of Nelchina, Alaska 18:32 UTC
4. 1.6 21 km NNW of Valdez, Alaska 20:33 UTC
5. 1.6 29 km N of Valdez, AK 18:06 UTC
6. 1.6 35 km N of Valdez, Alaska 13:19 UTC
7. 2.2 46 km WSW of Tonsina, Alaska 05:33 UTC
8. 1.5 41 km N of Valdez, Alaska 14:29 UTC
9. 3.0 51 km N of Valdez, Alaska 02:07 UTC
10. 1.6 51 km SE of Nelchina, Alaska 03:20 UTC
11. 1.8 Southern Alaska 00:48 UTC
12. 2.3 32 km NW of Valdez, Alaska 04:24 UTC
13. 1.8 37 km NNW of Valdez, Alaska 21:55 UTC
14. 2.9 35 km NNW of Valdez, Alaska 15:05 UTC
15. 1.9 29 km NW of Valdez, Alaska 08:46 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 02:47 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.