Earthquake near Anchorage, AK

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Anchorage, 9 km away, the estimate is intensity II (weak). 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.

Earthquakes near other towns within 30 km: Elmendorf Air Force Base, Eagle River, Big Lake, Knik-Fairview.

How big was it?

This earthquake released about 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
3. Around the size people start to feel M 3.0 22× the energy of this one
4. This earthquake M 2.1 about 43 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 7.1 on 2018-11-30 — about 32,000,000 times the energy of this one.

Before 2016, the USGS record lists 21 earthquakes of M5 or more within 50 km; the five largest:

1. 5.8 20 km ENE of Beluga, Alaska · 48 km W of this epicentre Dec 4, 2012
2. 5.6 11 km NW of Big Lake, Alaska · 34 km NNW of this epicentre Oct 7, 1966
3. 5.6 5 km N of Susitna, Alaska · 47 km NW of this epicentre Dec 29, 1974
4. 5.5 2 km ENE of Eagle River, Alaska · 20 km E of this epicentre May 11, 1965
5. 5.5 9 km E of Susitna, Alaska · 37 km NW of this epicentre Dec 30, 1985

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 61.2960, -149.8820. Map © OpenStreetMap contributors.

Nearby places

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

1. 2.1 7 km NW of Knik-Fairview, Alaska 17:17 UTC
2. 1.9 21 km E of Point Possession, Alaska 07:52 UTC
3. 2.0 7 km NW of Point MacKenzie, Alaska 05:17 UTC
4. 1.6 11 km E of Willow, Alaska 02:18 UTC
5. 1.7 5 km SSE of Willow, Alaska 05:54 UTC
6. 1.7 9 km SSE of Willow, Alaska 03:46 UTC
7. 1.8 23 km SSW of Anchorage, Alaska 00:33 UTC
8. 2.1 3 km E of Big Lake, Alaska 14:27 UTC
9. 1.8 5 km SSE of Willow, Alaska 09:32 UTC
10. 2.8 6 km NW of Big Lake, Alaska 15:17 UTC
11. 1.9 7 km NW of Houston, Alaska 12:42 UTC
12. 1.9 4 km E of Big Lake, Alaska 04:40 UTC
13. 2.4 8 km WNW of Point MacKenzie, Alaska 03:18 UTC
14. 1.9 9 km WSW of Hope, Alaska 20:05 UTC
15. 1.9 12 km SSW of Elmendorf Air Force Base, Alaska 19:21 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 16:50 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

Revisions

USGS refines a solution as more stations report. Every change we have seen is listed here.

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.