218 km W of Port McNeill, Canada

A magnitude 4.9 earthquake was recorded 218 km W of Port McNeill, Canada at 13:10 UTC on 2018-08-21. 5 people have reported feeling it to USGS. This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

How big was it?

This earthquake released about 340 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.9 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 500× the energy of this one
2. Mineral, Virginia 2011 M 5.8 22× the energy of this one
3. Magna, Utah 2020 M 5.7 16× the energy of this one
4. This earthquake M 4.9 about 340 tons of TNT
5. Around the size people start to feel M 3.0 this one released 710× 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 in our catalogue was M 4.8 on 2017-12-04.

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 50.8522, -130.1495. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 4.0 207 km W of Port McNeill, Canada 10:58 UTC
2. 4.2 212 km W of Port McNeill, Canada 17:50 UTC
3. 5.2 210 km W of Port McNeill, Canada 05:37 UTC
4. 4.6 211 km W of Port McNeill, Canada 12:05 UTC
5. 5.0 224 km W of Port McNeill, Canada 21:39 UTC
6. 4.4 192 km W of Port McNeill, Canada 16:12 UTC
7. 4.2 207 km W of Port McNeill, Canada 06:23 UTC
8. 4.3 211 km W of Port McNeill, Canada 01:41 UTC
9. 4.5 219 km W of Port McNeill, Canada 05:58 UTC
10. 4.8 201 km W of Port McNeill, Canada 03:13 UTC
11. 4.3 224 km W of Port McNeill, Canada 11:15 UTC
12. 4.4 230 km W of Port McNeill, Canada 15:19 UTC
13. 5.5 229 km W of Port McNeill, Canada 11:28 UTC
14. 4.5 213 km W of Port McNeill, Canada 09:59 UTC
15. 4.3 234 km W of Port McNeill, Canada 17:41 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 21:51 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.