QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

16 km NE of Girdwood, Alaska

· 11 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 26 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 1.8 (ml)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Anchorage Municipality, 26 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 241 days ago

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

How big was it?

This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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.

Where

Epicentre 61.0280, -148.9150. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Anchorage Municipality, AK 26 km (16 mi) SE of here earthquakes near Anchorage Municipality

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

Aftershocks so far

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

  1. 1.8 31 km NNE of Whittier, Alaska
  2. 1.8 18 km NW of Girdwood, Alaska
  3. 1.8 10 km SSE of Sunrise, Alaska
  4. 1.5 15 km W of Whittier, Alaska
  5. 2.8 14 km ESE of Eagle River, Alaska
  6. 1.7 12 km W of Whittier, Alaska
  7. 1.8 7 km ESE of Sunrise, Alaska
  8. 1.8 28 km S of Knik River, Alaska
  9. 1.7 9 km NNE of Sunrise, Alaska
  10. 1.6 17 km WSW of Knik River, Alaska
  11. 1.7 20 km N of Moose Pass, Alaska
  12. 2.4 3 km NNW of Sunrise, Alaska
  13. 1.6 39 km ENE of Girdwood, Alaska
  14. 1.9 37 km ENE of Girdwood, Alaska
  15. 1.9 33 km SSE of Knik River, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.2 on 2020-06-18 — it released about 4,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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