QuakeIndex

Earthquake · reviewed by a seismologist

M 4.2ml

66 km WNW of Lake Louise, Alaska

· 16 km deep · released about 30 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Matanuska-Susitna Borough 95 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Magnitude
M 4.2 (ml)
Depth
16 km below the surface
Felt
251 reports · strongest reported intensity III
Measured shaking
intensity IV (ShakeMap)
Nearest
Matanuska-Susitna Borough, 95 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 7 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 251 people have reported feeling it to USGS.

How big was it?

This earthquake released about 30 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 5,600× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 250× the energy of this one
  3. Magna, Utah 2020 M 5.7 180× the energy of this one
  4. This earthquake M 4.2 about 30 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 63× 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 62.5060, -147.7420. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Matanuska-Susitna Borough, AK 95 km (59 mi) ENE of here earthquakes near Matanuska-Susitna Borough

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

  1. 1.7 50 km NNE of Chickaloon, Alaska
  2. 2.0 82 km N of Chickaloon, Alaska
  3. 1.8 78 km NW of Eureka Roadhouse, Alaska
  4. 1.8 62 km N of Chickaloon, Alaska
  5. 1.5 42 km NNW of Glacier View, Alaska
  6. 2.4 42 km NNW of Glacier View, Alaska
  7. 4.0 41 km NNW of Glacier View, Alaska
  8. 1.7 49 km NNE of Chickaloon, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 6.1 on 2021-05-31 — it released about 710 times the energy of this one.

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

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.