QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Seward, AK

No earthquake was likely felt in Seward in the 24 hours to 9:30 am AKST (18:30 UTC). The last one was M 4.3, 83 km (52 mi) W, at 2:30 am AKST on 1 November 2026, estimated intensity II (weak) in town; 115 felt reports to USGS. Every earthquake near Seward

This page: a magnitude 1.8 earthquake was recorded 46 km (28 mi) north-northeast of Seward, AK, at 9:54 am AKST on 17 December 2019 (18:54 UTC), 17 km deep.

USGS: 7 km ENE of Moose Pass, Alaska

87 km (54 mi) SSE of Anchorage, AK

9:54 am AKST, Dec 17, 2019 · · 17 km deep · released about 15 lb of TNT

Every earthquake near Seward Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 75 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
9:54 am AKST on 17 December 2019 ()
Where
46 km (28 mi) north-northeast of Seward, AK · earthquakes near Seward
Magnitude
M 1.8 (ml)
Depth
17 km below the surface
Felt
no reports yet
Nearest
Anchorage Municipality, 75 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2505 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 Seward, 46 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 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.

For this area

The largest earthquake within 50 km since 2016 was M 4.0 on 2016-10-02 — about 2,000 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 6.6 3 km SW of Bear Creek, Alaska · 41 km SSW of this epicentre
  2. 5.7 13 km S of Girdwood, Alaska · 35 km N of this epicentre
  3. 5.6 17 km W of Whittier, Alaska · 30 km NNE of this epicentre
  4. 5.3 16 km WSW of Whittier, Alaska · 30 km NNE 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 60.5018, -149.2355. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 75 km (46 mi) N earthquakes near Anchorage Municipality

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

Aftershocks so far

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

  1. 3.9 4 km NW of Sunrise, Alaska
  2. 2.1 14 km SSW of Hope, Alaska
  3. 1.8 26 km SSW of Whittier, Alaska
  4. 1.7 3 km WNW of Sunrise, Alaska
  5. 1.9 16 km SSW of Whittier, Alaska
  6. 1.7 1 km SE of Girdwood, Alaska
  7. 1.7 21 km SSW of Hope, Alaska
  8. 2.8 16 km S of Whittier, Alaska
  9. 1.6 9 km NW of Moose Pass, Alaska
  10. 1.7 13 km NW of Bear Creek, Alaska
  11. 1.9 15 km NW of Moose Pass, Alaska
  12. 3.5 10 km NE of Cooper Landing, Alaska
  13. 1.9 17 km N of Moose Pass, Alaska
  14. 1.5 17 km SW of Whittier, Alaska
  15. 2.5 2 km NW of Seward, 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.