134 km W of Adak, 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 1.9 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 89,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 4,000× the energy of this one
3. Magna, Utah 2020 M 5.7 2,800× the energy of this one
4. This earthquake M 3.4 about 1.9 tons of TNT
5. Around the size people start to feel M 3.0 this one released 4× 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 6.5 on 2018-08-15 — about 45,000 times the energy of this one.

Before 2016, the USGS record lists 148 earthquakes of M5 or more within 50 km; the five largest:

1. 7.2 162 km WSW of Adak, Alaska · 38 km SW of this epicentre Mar 16, 1957
2. 7.0 114 km WSW of Adak, Alaska · 38 km SE of this epicentre Jul 5, 1929
3. 7.0 148 km WSW of Adak, Alaska · 40 km S of this epicentre Mar 11, 1957
4. 6.9 151 km WSW of Adak, Alaska · 37 km SSW of this epicentre May 15, 1993
5. 6.6 152 km WSW of Adak, Alaska · 32 km SSW of this epicentre Mar 13, 1957

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 51.6955, -178.5575. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.7 129 km W of Adak, Alaska 05:24 UTC
2. 1.8 125 km WSW of Adak, Alaska 17:41 UTC
3. 2.0 114 km W of Adak, Alaska 00:59 UTC
4. 2.3 119 km W of Adak, Alaska 21:59 UTC
5. 1.6 Andreanof Islands, Aleutian Islands, Alaska 20:43 UTC
6. 1.9 Andreanof Islands, Aleutian Islands, Alaska 00:31 UTC
7. 2.1 111 km WSW of Adak, Alaska 10:11 UTC
8. 1.8 115 km WSW of Adak, Alaska 07:45 UTC
9. 3.3 125 km WSW of Adak, Alaska 09:34 UTC
10. 1.8 129 km WSW of Adak, Alaska 08:05 UTC
11. 1.6 136 km WSW of Adak, Alaska 22:01 UTC
12. 2.0 155 km WSW of Adak, Alaska 02:39 UTC
13. 1.7 145 km WSW of Adak, Alaska 01:51 UTC
14. 1.9 145 km WSW of Adak, Alaska 14:44 UTC
15. 1.9 114 km WSW of Adak, Alaska 18:01 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 07:18 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.