98 km S of Adak, Alaska

This was a minor earthquake. Quakes this small are rarely felt and do not cause 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 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
2. Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
3. Around the size people start to feel M 3.0 89× the energy of this one
4. This earthquake M 1.7 about 11 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 2017-05-08 — about 2,000,000 times the energy of this one.

Before 2016, the USGS record lists 95 earthquakes of M5 or more within 50 km; the five largest:

1. 7.1 75 km S of Adak, Alaska · 29 km NW of this epicentre Mar 14, 1957
2. 7.0 101 km S of Adak, Alaska · 8 km ESE of this epicentre Sep 9, 1910
3. 6.9 61 km SSW of Adak, Alaska · 47 km NW of this epicentre Feb 7, 1971
4. 6.8 90 km SSW of Adak, Alaska · 38 km WNW of this epicentre Mar 11, 1957
5. 6.7 76 km SSE of Adak, Alaska · 34 km NE of this epicentre Dec 10, 1905

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 50.9975, -176.4637. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.8 85 km SSE of Adak, Alaska 20:02 UTC
2. 2.4 99 km SSE of Adak, Alaska 18:34 UTC
3. 3.9 109 km SSE of Adak, Alaska 18:29 UTC
4. 4.0 113 km SSE of Adak, Alaska 17:28 UTC
5. 3.8 105 km SSE of Adak, Alaska 17:15 UTC
6. 3.6 107 km SSE of Adak, Alaska 16:58 UTC
7. 2.9 87 km SSE of Adak, Alaska 16:24 UTC
8. 2.6 83 km SSE of Adak, Alaska 15:46 UTC
9. 3.9 98 km SSE of Adak, Alaska 15:23 UTC
10. 2.8 89 km SSE of Adak, Alaska 15:23 UTC
11. 3.2 98 km SSE of Adak, Alaska 15:09 UTC
12. 4.7 91 km SSE of Adak, Alaska 15:06 UTC
13. 2.3 109 km SSE of Adak, Alaska 14:57 UTC
14. 2.5 102 km SSE of Adak, Alaska 06:54 UTC
15. 4.0 108 km SSE of Adak, Alaska 01:40 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 05:51 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.