QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

166 km SW of Nikolski, Alaska

Yes. A magnitude 2.8 earthquake was recorded 166 km SW of Nikolski, Alaska at 09:06 UTC on 2018-04-10, 35 km deep.

· 35 km deep · released about 480 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N
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 2.8 (ml)
Depth
35 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1189 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. 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

The largest earthquake within 50 km since 2016 was M 5.2 on 2017-05-19 — about 4,000 times the energy of this one.

Before 2016, the USGS record lists 75 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 179 km SW of Nikolski, Alaska · 39 km SSE of this epicentre
  2. 6.1 Fox Islands, Aleutian Islands, Alaska · 34 km S of this epicentre
  3. 6.1 188 km E of Atka, Alaska · 40 km WNW of this epicentre
  4. 6.0 177 km WSW of Nikolski, Alaska · 29 km NW of this epicentre
  5. 6.0 128 km SW of Nikolski, Alaska · 46 km E 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 52.1111, -170.9037. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.8 161 km SW of Nikolski, Alaska
  2. 3.3 181 km WSW of Nikolski, Alaska
  3. 2.8 193 km SW of Nikolski, Alaska
  4. 2.9 162 km SW of Nikolski, Alaska
  5. 4.0 140 km SW of Nikolski, Alaska
  6. 3.0 177 km WSW of Nikolski, Alaska
  7. 3.7 193 km WSW of Nikolski, Alaska
  8. 2.5 172 km SW of Nikolski, Alaska
  9. 4.0 184 km SW of Nikolski, Alaska
  10. 4.0 196 km ESE of Atka, Alaska
  11. 2.6 171 km SW of Nikolski, Alaska
  12. 2.1 156 km WSW of Nikolski, Alaska
  13. 2.3 129 km SW of Nikolski, Alaska
  14. 4.3 199 km SW of Nikolski, Alaska
  15. 2.5 Fox Islands, Aleutian Islands, 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.