QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

Earthquake near Girdwood, AK

No earthquake was likely felt in Girdwood in the 24 hours to 9:11 am AKST (18:11 UTC). The last one was M 1.8, 8 km (5 mi) SE, at 10:01 am AKDT on 19 October 2026, estimated intensity II (weak) in town. Every earthquake near Girdwood

This page: a magnitude 2.8 earthquake was recorded 42 km (26 mi) east-northeast of Girdwood, AK, at 5:08 pm AKST on 20 January 2020 (02:08 UTC), 7.4 km deep. 1 person has reported feeling it to USGS.

USGS: 41 km NNE of Whittier, Alaska

76 km (47 mi) E of Anchorage, AK

5:08 pm AKST, Jan 20, 2020 · · 7.4 km deep · released about 480 lb of TNT

Every earthquake near Girdwood Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 43 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
5:08 pm AKST on 20 January 2020 ()
Where
42 km (26 mi) east-northeast of Girdwood, AK · earthquakes near Girdwood
Magnitude
M 2.8 (ml)
Depth
7.4 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Anchorage Municipality, 43 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2410 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 26 km (16 mi) from the epicentre. In Girdwood, 42 km away, the estimate is intensity II (weak). 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 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.6 57 km ENE of Whittier, Alaska · 41 km ESE of this epicentre
  2. 6.4 22 km ENE of Whittier, Alaska · 32 km SSE of this epicentre
  3. 6.3 27 km ENE of Whittier, Alaska · 30 km SSE of this epicentre
  4. 6.1 54 km WNW of Tatitlek, Alaska · 49 km E of this epicentre
  5. 6.0 21 km N of Whittier, Alaska · 21 km SSW 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 61.1339, -148.4907. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 43 km (27 mi) W earthquakes near Anchorage Municipality

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. 1.6 35 km NNE of Whittier, Alaska
  2. 1.5 38 km NNE of Whittier, Alaska
  3. 1.5 43 km NNE of Whittier, Alaska
  4. 1.8 37 km NNE of Whittier, Alaska
  5. 1.6 36 km E of Whittier, Alaska
  6. 1.7 47 km SSW of Glacier View, Alaska
  7. 1.5 37 km NNE of Whittier, Alaska
  8. 1.5 40 km NNE of Whittier, Alaska
  9. 1.7 41 km NNE of Whittier, Alaska
  10. 1.7 36 km NNE of Whittier, Alaska
  11. 1.6 36 km NNE of Whittier, Alaska
  12. 1.6 38 km NNE of Whittier, Alaska
  13. 1.7 Southern Alaska
  14. 1.7 34 km NNE of Whittier, Alaska
  15. 1.5 35 km NNE of Whittier, 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.