Earthquake near Anchorage, AK

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

At this magnitude and depth, people at rest would likely notice it out to about 228 km (142 mi) from the epicentre. In Anchorage, 11 km away, the estimate is intensity IV (light). 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.

Likely felt in: Anchorage 11 km, intensity IV · Eagle River 20 km, intensity IV · Big Lake 23 km, intensity IV · Knik-Fairview 28 km, intensity IV · Tanaina 43 km, intensity III · Willow 48 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1.3 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.3 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 130× the energy of this one
2. Mineral, Virginia 2011 M 5.8 5.6× the energy of this one
3. Magna, Utah 2020 M 5.7 4× the energy of this one
4. This earthquake M 5.3 about 1.3 kilotons of TNT
5. Around the size people start to feel M 3.0 this one released 2,800× more

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 500 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 · 45 km W of this epicentre Dec 4, 2012
2. 5.6 11 km NW of Big Lake, Alaska · 31 km NNW of this epicentre Oct 7, 1966
3. 5.6 5 km N of Susitna, Alaska · 44 km NW of this epicentre Dec 29, 1974
4. 5.5 2 km ENE of Eagle River, Alaska · 22 km E of this epicentre May 11, 1965
5. 5.5 9 km E of Susitna, Alaska · 33 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 61.3190, -149.9334. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 2.6 3 km SSE of Big Lake, Alaska 03:01 UTC
2. 1.7 5 km WSW of Hope, Alaska 17:08 UTC
3. 1.6 7 km SSE of Willow, Alaska 00:14 UTC
4. 1.7 3 km SSW of Big Lake, Alaska 09:31 UTC
5. 1.8 6 km S of Willow, Alaska 07:01 UTC
6. 2.4 5 km SSE of Willow, Alaska 06:52 UTC
7. 2.1 18 km NW of Hope, Alaska 00:09 UTC
8. 1.9 9 km SW of Big Lake, Alaska 19:10 UTC
9. 1.5 17 km WNW of Point MacKenzie, Alaska 17:26 UTC
10. 1.5 21 km W of Point MacKenzie, Alaska 02:19 UTC
11. 1.6 6 km NW of Point MacKenzie, Alaska 19:52 UTC
12. 1.6 14 km WNW of Point MacKenzie, Alaska 08:08 UTC
13. 1.8 21 km W of Point MacKenzie, Alaska 20:38 UTC
14. 2.1 8 km N of Houston, Alaska 00:16 UTC
15. 1.9 23 km E of Point Possession, Alaska 22:22 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 04:47 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.