QuakeIndex

Earthquake · reviewed by a seismologist

M 4.1ml

Earthquake near Anchorage, AK

No earthquake was likely felt in Anchorage in the 24 hours to 5:18 pm AKST (02:18 UTC). The last one was M 3.5, 39 km (24 mi) SSW, at 4:48 pm AKDT on 27 October 2026, estimated intensity II (weak) in town; 98 felt reports to USGS. Every earthquake near Anchorage

This page: a magnitude 4.1 earthquake was recorded 36 km (22 mi) northwest of Anchorage, AK, at 6:30 pm AKST on 15 December 2019 (03:30 UTC), 62 km deep. 226 people have reported feeling it to USGS.

USGS: 15 km SSE of Susitna, Alaska

36 km (22 mi) NW of Anchorage, AK

6:30 pm AKST, Dec 15, 2019 · · 62 km deep · released about 21 tons of TNT

Every earthquake near Anchorage Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 67 kmMatanuska-Susitna Borough 107 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
6:30 pm AKST on 15 December 2019 ()
Where
36 km (22 mi) northwest of Anchorage, AK · earthquakes near Anchorage
Magnitude
M 4.1 (ml)
Depth
62 km below the surface
Felt
226 reports · strongest reported intensity III
Measured shaking
intensity III (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Anchorage Municipality, 67 km ESE
Nearest mapped fault
Castle Mountain fault, 7 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 2223 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 84 km (52 mi) from the epicentre. In Anchorage, 36 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.

Likely felt in: Big Lake 29 km, intensity II · Anchorage 36 km, intensity II · Willow 43 km, intensity II · Knik-Fairview 46 km, intensity II · Eagle River 47 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 21 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 7,900× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 350× the energy of this one
  3. Magna, Utah 2020 M 5.7 250× the energy of this one
  4. This earthquake M 4.1 about 21 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 45× more

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 7.1 on 2018-11-30 — about 32,000 times the energy of this one.

Before 2016, the USGS record lists 26 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 4 km NE of Beluga, Alaska · 41 km SW of this epicentre
  2. 5.8 27 km N of Beluga, Alaska · 32 km W of this epicentre
  3. 5.8 20 km ENE of Beluga, Alaska · 26 km SW of this epicentre
  4. 5.6 11 km NW of Big Lake, Alaska · 25 km NE of this epicentre
  5. 5.6 5 km N of Susitna, Alaska · 21 km N 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 61.4108, -150.4387. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 67 km (42 mi) ESE earthquakes near Anchorage Municipality
Matanuska-Susitna Borough, AK 107 km (66 mi) NNE earthquakes near Matanuska-Susitna Borough
Kenai Peninsula Borough, AK 154 km (96 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

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

  1. 2.5 9 km SSE of Big Lake, Alaska
  2. 1.8 17 km SW of Susitna, Alaska
  3. 2.5 4 km SE of Big Lake, Alaska
  4. 1.6 3 km W of Point MacKenzie, Alaska
  5. 2.0 2 km S of Big Lake, Alaska
  6. 1.5 24 km NW of Susitna, Alaska
  7. 2.4 5 km NNE of Big Lake, Alaska
  8. 1.7 13 km SW of Big Lake, Alaska
  9. 1.6 5 km NNE of Big Lake, Alaska
  10. 2.3 Southern Alaska
  11. 1.6 2 km ESE of Big Lake, Alaska
  12. 2.1 3 km ESE of Big Lake, Alaska
  13. 2.2 26 km SSW of Susitna, Alaska
  14. 2.2 2 km WSW of Point MacKenzie, Alaska
  15. 1.7 3 km SE of Big Lake, 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.