Earthquake · reviewed by a seismologist
M 4.9mb
159 km SE of King Cove, Alaska
Yes. A magnitude 4.9 earthquake was recorded 159 km SE of King Cove, Alaska at 08:50 UTC on 2022-12-21, 17 km deep.
- When
- Magnitude
- M 4.9 (mb)
- Depth
- 17 km below the surface
- Felt
- no reports yet
- Measured shaking
- intensity I (ShakeMap)
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1354 days ago
This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.
At this magnitude and depth, people at rest would likely notice it out to about 181 km (112 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 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.
- Northridge, California 1994 M 6.7 500× the energy of this one
- Mineral, Virginia 2011 M 5.8 22× the energy of this one
- Magna, Utah 2020 M 5.7 16× the energy of this one
- This earthquake M 4.9 about 340 tons of TNT
- 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 since 2016 was M 5.7 on 2017-05-28 — about 16 times the energy of this one.
Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:
- 6.4 159 km SSE of King Cove, Alaska · 18 km WSW of this epicentre
- 6.2 141 km SSE of King Cove, Alaska · 20 km WNW of this epicentre
- 6.1 166 km SSE of King Cove, Alaska · 49 km SW of this epicentre
- 5.9 131 km S of Sand Point, Alaska · 43 km NE of this epicentre
- 5.9 146 km SSE of King Cove, Alaska · 48 km W of this epicentre
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 53.8975, -160.8725. Map © OpenStreetMap contributors.
Aftershocks so far
48 earthquakes have been recorded within 50 km since this one.
- 2.8 115 km SSW of Sand Point, Alaska
- 2.0 123 km S of Sand Point, Alaska
- 2.9 121 km S of Sand Point, Alaska
- 2.2 136 km S of Sand Point, Alaska
- 2.5 123 km S of Sand Point, Alaska
- 3.3 112 km SSW of Sand Point, Alaska
- 1.7 113 km SSW of Sand Point, Alaska
- 5.0 121 km SSW of Sand Point, Alaska
- 3.0 116 km SSW of Sand Point, Alaska
- 2.7 116 km SSW of Sand Point, Alaska
- 3.4 193 km SSE of King Cove, Alaska
- 2.2 113 km SSW of Sand Point, Alaska
- 2.1 142 km S of Sand Point, Alaska
- 1.8 117 km S of Sand Point, Alaska
- 2.2 131 km SE of King Cove, Alaska
Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . 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.