70 km E of Port Alsworth, Alaska

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. 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 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
3. Around the size people start to feel M 3.0 5.6× the energy of this one
4. This earthquake M 2.5 about 170 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 5.9 on 2021-12-21 — about 130,000 times the energy of this one.

Before 2016, the USGS record lists 27 earthquakes of M5 or more within 50 km; the five largest:

1. 6.4 75 km WNW of Ninilchik, Alaska · 6 km ENE of this epicentre Feb 7, 1988
2. 6.4 52 km ENE of Pedro Bay, Alaska · 43 km S of this epicentre Jul 29, 2015
3. 6.2 70 km E of Port Alsworth, Alaska · 14 km S of this epicentre Dec 17, 1968
4. 6.1 73 km WNW of Ninilchik, Alaska · 17 km NE of this epicentre Jul 9, 1998
5. 5.9 66 km ENE of Pedro Bay, Alaska · 28 km S of this epicentre Nov 20, 1993

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 60.2740, -153.0530. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 0.5 64 km ENE of Pedro Bay, Alaska 07:15 UTC
2. 1.8 60 km WNW of Happy Valley, Alaska 05:56 UTC
3. 0.7 71 km NW of Ninilchik, Alaska 00:18 UTC
4. -0.8 62 km ENE of Pedro Bay, Alaska 21:34 UTC
5. 0.7 62 km ENE of Pedro Bay, Alaska 18:26 UTC
6. -0.9 61 km ENE of Pedro Bay, Alaska 18:23 UTC
7. 1.9 66 km WNW of Happy Valley, Alaska 17:32 UTC
8. -0.4 60 km ENE of Pedro Bay, Alaska 17:21 UTC
9. -1.3 61 km ENE of Pedro Bay, Alaska 16:06 UTC
10. -0.8 63 km ENE of Pedro Bay, Alaska 13:25 UTC
11. -0.3 65 km ENE of Pedro Bay, Alaska 12:58 UTC
12. 1.9 45 km ENE of Pedro Bay, Alaska 05:39 UTC
13. 0.3 73 km ENE of Port Alsworth, Alaska 03:46 UTC
14. -0.1 63 km ENE of Pedro Bay, Alaska 03:40 UTC
15. 0.6 51 km E of Port Alsworth, Alaska 03:13 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 21:03 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.