119 km SE of Chignik, Alaska

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

How big was it?

This earthquake released about 2.7 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 63,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 2,800× the energy of this one
3. Magna, Utah 2020 M 5.7 2,000× the energy of this one
4. This earthquake M 3.5 about 2.7 tons of TNT
5. Around the size people start to feel M 3.0 this one released 5.6× 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.

Where

Epicentre 55.5540, -157.0107. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 4.6 148 km SE of Chignik, Alaska 09:53 UTC
2. 3.3 113 km SE of Chignik, Alaska 09:38 UTC
3. 3.3 101 km SE of Chignik, Alaska 09:30 UTC
4. 4.7 128 km SSE of Chignik, Alaska 09:28 UTC
5. 3.5 161 km SE of Chignik, Alaska 09:22 UTC
6. 2.8 124 km SE of Chignik, Alaska 09:14 UTC
7. 3.4 143 km SSE of Chignik, Alaska 08:56 UTC
8. 4.1 149 km SSE of Chignik, Alaska 08:40 UTC
9. 3.5 118 km SSE of Chignik, Alaska 08:38 UTC
10. 3.3 166 km SE of Chignik, Alaska 08:34 UTC
11. 3.3 122 km SE of Chignik, Alaska 08:24 UTC
12. 4.2 149 km SE of Chignik, Alaska 08:15 UTC
13. 4.2 145 km SE of Chignik, Alaska 08:15 UTC
14. 3.0 106 km SE of Chignik, Alaska 08:12 UTC
15. 4.6 155 km SSE of Chignik, Alaska 08:09 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 20:16 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 4.6 on 2017-09-12 — it released about 45 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

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.