186 km SSE of False Pass, 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 8 km (5 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 4.1 on 2017-09-05 — about 180 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

1. 8.6 The 1946 Unimak Island, Alaska Earthquake · 40 km WNW of this epicentre Apr 1, 1946
2. 6.3 226 km SSE of False Pass, Alaska · 40 km SSE of this epicentre Feb 6, 1965
3. 6.3 210 km S of King Cove, Alaska · 36 km ESE of this epicentre Feb 6, 1965
4. 6.2 172 km SSE of False Pass, Alaska · 35 km W of this epicentre Apr 2, 1946
5. 5.7 187 km SSE of False Pass, Alaska · 2 km SSW of this epicentre Mar 13, 1965

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 53.3062, -162.3192. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.8 154 km SSE of False Pass, Alaska 17:43 UTC
2. 2.9 200 km SSE of False Pass, Alaska 02:24 UTC
3. 2.4 147 km SSE of False Pass, Alaska 10:39 UTC
4. 3.0 158 km SSE of False Pass, Alaska 11:40 UTC
5. 2.8 220 km SSE of False Pass, Alaska 16:55 UTC
6. 2.8 219 km S of King Cove, Alaska 05:13 UTC
7. 2.6 206 km SSE of False Pass, Alaska 23:48 UTC
8. 2.2 228 km SSE of False Pass, Alaska 20:37 UTC
9. 2.6 231 km SSE of False Pass, Alaska 11:38 UTC
10. 2.1 173 km S of King Cove, Alaska 06:43 UTC
11. 2.6 207 km S of King Cove, Alaska 16:20 UTC
12. 2.8 south of Alaska 14:58 UTC
13. 2.2 229 km SSE of False Pass, Alaska 11:57 UTC
14. 2.8 178 km SSE of False Pass, Alaska 16:58 UTC
15. 2.8 195 km SSE of False Pass, Alaska 06:53 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 06:15 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.