237 km WSW 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, people at rest would likely notice it out to about 12 km (7 mi) from the epicentre. 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 240 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 63,000× the energy of this one
2. Magna, Utah 2020 M 5.7 45,000× the energy of this one
3. Around the size people start to feel M 3.0 4× the energy of this one
4. This earthquake M 2.6 about 240 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 6.1 on 2020-01-26 — about 180,000 times the energy of this one.

Before 2016, the USGS record lists 136 earthquakes of M5 or more within 50 km; the five largest:

1. 7.2 238 km WSW of Adak, Alaska · 10 km NNW of this epicentre Mar 22, 1905
2. 7.2 207 km WSW of Adak, Alaska · 39 km NNE of this epicentre Dec 19, 2007
3. 6.9 203 km WSW of Adak, Alaska · 40 km NE of this epicentre Mar 31, 1913
4. 6.9 231 km WSW of Adak, Alaska · 26 km N of this epicentre May 14, 1969
5. 6.8 235 km WSW of Adak, Alaska · 24 km NNW of this epicentre May 6, 1987

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 51.0665, -179.8041. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.7 226 km WSW of Adak, Alaska 10:16 UTC
2. 2.7 223 km WSW of Adak, Alaska 08:08 UTC
3. 1.8 233 km WSW of Adak, Alaska 17:47 UTC
4. 2.5 237 km WSW of Adak, Alaska 22:36 UTC
5. 1.7 219 km WSW of Adak, Alaska 04:38 UTC
6. 1.9 207 km WSW of Adak, Alaska 08:42 UTC
7. 1.9 236 km WSW of Adak, Alaska 18:20 UTC
8. 1.7 238 km WSW of Adak, Alaska 23:01 UTC
9. 2.1 218 km WSW of Adak, Alaska 17:21 UTC
10. 2.6 201 km WSW of Adak, Alaska 22:04 UTC
11. 2.9 231 km WSW of Adak, Alaska 17:55 UTC
12. 3.2 236 km WSW of Adak, Alaska 17:49 UTC
13. 3.1 217 km WSW of Adak, Alaska 12:12 UTC
14. 1.7 222 km WSW of Adak, Alaska 08:26 UTC
15. 2.2 233 km WSW of Adak, Alaska 07:46 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 12:28 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.