QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

12 km E of Beluga, Alaska

Yes. A magnitude 2.1 earthquake was recorded 12 km E of Beluga, Alaska, 52 km (32 mi) W of Anchorage, AK, at 1:45 am AKDT on 28 August 2021 (09:45 UTC), 54 km deep.

52 km (32 mi) W of Anchorage, AK

· 54 km deep · released about 43 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 85 kmKenai Peninsula Borough 117 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 2.1 (ml)
Depth
54 km below the surface
Felt
no reports yet
Nearest
Anchorage Municipality, 85 km E
Nearest mapped fault
Castle Mountain fault, 23 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1890 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. 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 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 43 lb of TNT

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 4.5 on 2018-10-15 — about 4,000 times the energy of this one.

Before 2016, the USGS record lists 21 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 Southern Alaska · 15 km WSW of this epicentre
  2. 6.8 4 km NE of Beluga, Alaska · 9 km WNW of this epicentre
  3. 6.4 19 km SSE of Tyonek, Alaska · 29 km SSW of this epicentre
  4. 6.0 Southern Alaska · 44 km WNW of this epicentre
  5. 5.8 17 km NW of Beluga, Alaska · 28 km WNW 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 61.1394, -150.8596. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 85 km (53 mi) E earthquakes near Anchorage Municipality
Kenai Peninsula Borough, AK 117 km (73 mi) SW earthquakes near Kenai Peninsula Borough

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

Aftershocks so far

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

  1. 2.0 8 km SE of Tyonek, Alaska
  2. 1.8 6 km NW of Beluga, Alaska
  3. 2.0 12 km WSW of Susitna, Alaska
  4. 1.5 14 km W of Point Possession, Alaska
  5. 1.5 27 km SSW of Susitna, Alaska
  6. 1.5 27 km NNW of Beluga, Alaska
  7. 1.5 20 km SSE of Point Possession, Alaska
  8. 1.6 20 km WNW of Beluga, Alaska
  9. 1.5 16 km SE of Susitna, Alaska
  10. 1.5 16 km W of Susitna, Alaska
  11. 1.5 11 km SE of Point Possession, Alaska
  12. 2.2 23 km W of Susitna, Alaska
  13. 2.2 23 km E of Beluga, Alaska
  14. 1.6 26 km WSW of Susitna, Alaska
  15. 1.5 22 km NNE of Beluga, 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.