QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

52 km ENE of Chenega, Alaska

Yes. A magnitude 1.5 earthquake was recorded 52 km ENE of Chenega, Alaska, at 10:37 am AKDT on 10 August 2021 (18:37 UTC), 27 km deep.

· 27 km deep · released about 5.4 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Chugach Census Area 58 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 1.5 (ml)
Depth
27 km below the surface
Felt
no reports yet
Nearest
Chugach Census Area, 58 km ENE
Nearest mapped fault
Patton Bay fault, 24 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 1912 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 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 180× the energy of this one
  4. This earthquake M 1.5 about 5.4 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 5.3 on 2017-11-27 — about 500,000 times the energy of this one.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.0 52 km NE of Chenega, Alaska · 12 km NNW of this epicentre
  2. 6.7 Prince William Sound, Alaska · 45 km N of this epicentre
  3. 6.4 Prince William Sound, Alaska · 19 km NNW of this epicentre
  4. 6.3 60 km SW of Cordova, Alaska · 29 km ESE of this epicentre
  5. 6.3 56 km WSW of Cordova, Alaska · 27 km ENE 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 60.2800, -147.1789. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Chugach Census Area, AK 58 km (36 mi) ENE earthquakes near Chugach Census Area
Anchorage Municipality, AK 152 km (94 mi) NW earthquakes near Anchorage Municipality

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

Aftershocks so far

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

  1. 1.6 52 km SW of Tatitlek, Alaska
  2. 1.6 51 km SW of Tatitlek, Alaska
  3. 1.6 59 km SSW of Tatitlek, Alaska
  4. 2.3 25 km S of Tatitlek, Alaska
  5. 1.6 55 km NE of Chenega, Alaska
  6. 2.4 56 km SW of Tatitlek, Alaska
  7. 1.9 39 km SSW of Tatitlek, Alaska
  8. 2.3 40 km SSW of Tatitlek, Alaska
  9. 1.5 58 km WSW of Tatitlek, Alaska
  10. 1.7 40 km NNE of Chenega, Alaska
  11. 1.5 52 km SW of Tatitlek, Alaska
  12. 1.5 60 km SSW of Tatitlek, Alaska
  13. 1.9 55 km ENE of Chenega, Alaska
  14. 2.1 23 km SSW of Tatitlek, Alaska
  15. 1.5 60 km WSW of Tatitlek, 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.