57 km NNW of Karluk, 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 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 180,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
4. This earthquake M 3.2 about 1,900 lb of TNT
5. Around the size people start to feel M 3.0 this one released 2× 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 5.0 on 2023-06-18 — about 500 times the energy of this one.

Before 2016, the USGS record lists 51 earthquakes of M5 or more within 50 km; the five largest:

1. 7.0 Event 36 Novarupta-Mount Katmai area, Alaska Peninsula · 32 km NW of this epicentre Jun 8, 1912
2. 6.8 Event 37 Novarupta-Mount Katmai area, Alaska Peninsula · 32 km NW of this epicentre Jun 8, 1912
3. 6.8 Event 48 Novarupta-Mount Katmai area, Alaska Peninsula · 37 km NW of this epicentre Jun 10, 1912
4. 6.6 Event 39 Novarupta-Mount Katmai area, Alaska Peninsula · 32 km NW of this epicentre Jun 8, 1912
5. 6.5 Event 21 Novarupta-Mount Katmai area, Alaska Peninsula · 32 km NW of this epicentre Jun 7, 1912

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 58.0740, -154.6740. 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. 2.7 77 km NNW of Karluk, Alaska 04:47 UTC
2. 2.1 83 km NNW of Karluk, Alaska 23:51 UTC
3. 2.2 84 km NNW of Karluk, Alaska 23:49 UTC
4. 1.7 97 km N of Karluk, Alaska 18:46 UTC
5. 1.5 60 km NNW of Karluk, Alaska 18:35 UTC
6. 2.0 38 km WNW of Karluk, Alaska 17:57 UTC
7. 2.4 40 km NW of Karluk, Alaska 16:30 UTC
8. 2.4 63 km NW of Karluk, Alaska 11:50 UTC
9. 2.0 59 km N of Karluk, Alaska 23:16 UTC
10. 2.0 82 km NNW of Karluk, Alaska 02:37 UTC
11. 1.7 86 km NNW of Karluk, Alaska 16:54 UTC
12. 1.9 8 km N of Karluk, Alaska 05:33 UTC
13. 2.0 74 km NNW of Karluk, Alaska 02:35 UTC
14. 2.2 78 km NNW of Karluk, Alaska 02:14 UTC
15. 1.9 57 km N of Karluk, Alaska 01:53 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 04:19 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.