QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Cordova, AK

No earthquake was likely felt in Cordova in the 24 hours to 8:45 am AKST (17:45 UTC). The last one was M 3.1, 39 km (24 mi) SSW, at 7:37 pm AKDT on 28 June 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Cordova

This page: a magnitude 1.6 earthquake was recorded 33 km (20 mi) west-northwest of Cordova, AK, at 7:50 pm AKDT on 20 August 2023 (03:50 UTC), 21 km deep.

USGS: 29 km SE of Tatitlek, Alaska

7:50 pm AKDT, Aug 20, 2023 · · 21 km deep · released about 7.6 lb of TNT

Every earthquake near Cordova Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Chugach Census Area 21 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
7:50 pm AKDT on 20 August 2023 ()
Where
33 km (20 mi) west-northwest of Cordova, AK · earthquakes near Cordova
Magnitude
M 1.6 (ml)
Depth
21 km below the surface
Felt
no reports yet
Nearest
Chugach Census Area, 21 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1169 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. In Cordova, 33 km away, the estimate is intensity I (not felt). 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 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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 4.4 on 2022-07-09 — about 16,000 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. 6.7 Prince William Sound, Alaska · 41 km W of this epicentre
  2. 6.3 56 km WSW of Cordova, Alaska · 43 km SSW of this epicentre
  3. 6.1 13 km ENE of Cordova, Alaska · 44 km ESE of this epicentre
  4. 6.0 Near Valdez, Alaska · 37 km N of this epicentre
  5. 5.9 31 km NW of Cordova, Alaska · 11 km NE 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 60.6716, -146.3023. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Chugach Census Area, AK 21 km (13 mi) SSE earthquakes near Chugach Census Area

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. 1.7 48 km S of Tatitlek, Alaska
  2. 2.2 8 km S of Valdez, Alaska
  3. 1.8 17 km SSW of Tatitlek, Alaska
  4. 2.2 19 km SSW of Tatitlek, Alaska
  5. 1.6 11 km E of Tatitlek, Alaska
  6. 2.3 15 km S of Valdez, Alaska
  7. 1.5 14 km ESE of Tatitlek, Alaska
  8. 2.0 14 km S of Tatitlek, Alaska
  9. 1.7 11 km ESE of Tatitlek, Alaska
  10. 1.9 12 km SW of Tatitlek, Alaska
  11. 1.6 6 km E of Tatitlek, Alaska
  12. 1.9 11 km WSW of Valdez, Alaska
  13. 2.1 19 km S of Tatitlek, Alaska
  14. 1.9 17 km ESE of Tatitlek, Alaska
  15. 1.9 21 km WSW of Valdez, 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.