QuakeIndex

Earthquake · reviewed by a seismologist

M 6.1mww

73 km N of Chickaloon, Alaska

Yes. A magnitude 6.1 earthquake was recorded 73 km N of Chickaloon, Alaska, at 10:59 pm AKDT on 30 May 2021 (06:59 UTC), 44 km deep. 4,618 people have reported feeling it to USGS.

· 44 km deep · released about 21 kilotons of TNT

10 km30 km60 km120 km N Matanuska-Susitna Borough 68 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 6.1 (mww)
Depth
44 km below the surface
Felt
4,618 reports · strongest reported intensity VI
Measured shaking
intensity VI (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Matanuska-Susitna Borough, 68 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 318 days ago

This was a strong earthquake. Damage is likely near the epicentre and it is felt over a wide area.

At this magnitude and depth, people at rest would likely notice it out to about 363 km (226 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 21 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 7.1 would have released about 32 times as much.

  1. Ridgecrest, California 2019 M 7.1 32× the energy of this one
  2. Loma Prieta, California 1989 M 6.9 16× the energy of this one
  3. Northridge, California 1994 M 6.7 7.9× the energy of this one
  4. This earthquake M 6.1 about 21 kilotons of TNT
  5. Mineral, Virginia 2011 M 5.8 this one released 2.8× more
  6. Magna, Utah 2020 M 5.7 this one released 4× 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 (31 mi) since our catalogue begins in 2016. The previous largest was M 4.5 on 2019-10-27.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 5.3 40 km WNW of Lake Louise, Alaska · 49 km E of this epicentre
  2. 5.3 55 km NNE of Chickaloon, Alaska · 20 km SSE of this epicentre
  3. 5.0 70 km ENE of Chase, Alaska · 42 km NW of this epicentre
  4. 5.0 59 km NW of Eureka Roadhouse, Alaska · 21 km SE 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 62.4492, -148.2512. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Matanuska-Susitna Borough, AK 68 km (42 mi) WSW earthquakes near Matanuska-Susitna Borough

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

Aftershocks so far

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

  1. 1.6 74 km N of Chickaloon, Alaska
  2. 1.6 68 km N of Chickaloon, Alaska
  3. 1.6 75 km N of Chickaloon, Alaska
  4. 2.3 72 km N of Chickaloon, Alaska
  5. 1.9 76 km N of Chickaloon, Alaska
  6. 2.2 74 km N of Chickaloon, Alaska
  7. 1.6 75 km N of Chickaloon, Alaska
  8. 1.6 68 km N of Chickaloon, Alaska
  9. 1.7 74 km N of Chickaloon, Alaska
  10. 1.5 75 km N of Chickaloon, Alaska
  11. 1.8 74 km N of Chickaloon, Alaska
  12. 1.6 75 km N of Chickaloon, Alaska
  13. 2.1 68 km N of Chickaloon, Alaska
  14. 1.7 76 km N of Chickaloon, Alaska
  15. 2.1 74 km N 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.

On USGS

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