QuakeIndex

Earthquake · reviewed by a seismologist

M 3.0ml

Earthquake near Nikiski, AK

No earthquake was likely felt in Nikiski in the 24 hours to 10:33 pm AKST (07:33 UTC). The last one was M 4.3, 58 km (36 mi) SSE, at 2:30 am AKST on 1 November 2026, estimated intensity II (weak) in town; 115 felt reports to USGS. Every earthquake near Nikiski

This page: a magnitude 3.0 earthquake was recorded 34 km (21 mi) north-northeast of Nikiski, AK, at 11:15 am AKST on 28 February 2020 (20:15 UTC), 57 km deep.

USGS: 15 km SSE of Tyonek, Alaska

65 km (40 mi) WSW of Anchorage, AK

11:15 am AKST, Feb 28, 2020 · · 57 km deep · released about 950 lb of TNT

Every earthquake near Nikiski Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 94 kmKenai Peninsula Borough 98 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
11:15 am AKST on 28 February 2020 ()
Where
34 km (21 mi) north-northeast of Nikiski, AK · earthquakes near Nikiski
Magnitude
M 3.0 (ml)
Depth
57 km below the surface
Felt
no reports yet
Measured shaking
intensity II (ShakeMap)
Nearest
Anchorage Municipality, 94 km ENE
Nearest mapped fault
Granite Point anticline (Cook Inlet folds), 19 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 2368 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 it was probably too small to be felt, even directly above it. In Nikiski, 34 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 950 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 350,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 16,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 11,000× the energy of this one
  4. This earthquake M 3.0 about 950 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 4.5 on 2018-10-15 — about 180 times the energy of this one.

Before 2016, the USGS record lists 17 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 Southern Alaska · 17 km NNW of this epicentre
  2. 6.8 4 km NE of Beluga, Alaska · 25 km N of this epicentre
  3. 6.8 24 km ENE of Sterling, Alaska · 46 km SE of this epicentre
  4. 6.7 6 km WNW of Nikiski, Alaska · 35 km SW of this epicentre
  5. 6.4 19 km SSE of Tyonek, Alaska · 7 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 60.9510, -150.9777. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 94 km (59 mi) ENE earthquakes near Anchorage Municipality
Kenai Peninsula Borough, AK 98 km (61 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

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

  1. 2.6 21 km SSW of Susitna, Alaska
  2. 1.5 15 km E of Nikiski, Alaska
  3. 2.9 7 km NW of Point Possession, Alaska
  4. 1.5 5 km NNW of Ridgeway, Alaska
  5. 2.6 14 km SW of Point Possession, Alaska
  6. 2.2 13 km SE of Tyonek, Alaska
  7. 2.5 14 km ESE of Point Possession, Alaska
  8. 2.3 10 km SE of Beluga, Alaska
  9. 1.6 25 km NE of Beluga, Alaska
  10. 2.4 23 km SSW of Susitna, Alaska
  11. 2.9 24 km SSW of Susitna, Alaska
  12. 1.6 11 km SE of Point Possession, Alaska
  13. 1.6 22 km ENE of Beluga, Alaska
  14. 1.8 15 km WNW of Point Possession, Alaska
  15. 1.9 13 km SSE of Point Possession, 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.