QuakeIndex

Earthquake · reviewed by a seismologist

M 3.2ml

198 km S of Adak, Alaska

Yes. A magnitude 3.2 earthquake was recorded 198 km S of Adak, Alaska at 19:57 UTC on 2021-08-14, 10 km deep.

· 10 km deep · released about 1,900 lb of TNT

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 3.2 (ml)
Depth
10 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1842 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, people at rest would likely notice it out to about 45 km (28 mi) from the epicentre. 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 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
  4. This earthquake M 3.2 about 1,900 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 2× 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 5.4 on 2019-09-09 — about 2,000 times the energy of this one.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 204 km S of Adak, Alaska · 8 km SE of this epicentre
  2. 6.1 198 km S of Adak, Alaska · 4 km W of this epicentre
  3. 6.1 189 km S of Adak, Alaska · 17 km NW of this epicentre
  4. 6.0 194 km SSW of Adak, Alaska · 44 km WNW of this epicentre
  5. 5.8 176 km S of Adak, Alaska · 22 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 50.0954, -176.8445. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.8 170 km S of Adak, Alaska
  2. 2.4 205 km S of Adak, Alaska
  3. 2.1 178 km S of Adak, Alaska
  4. 3.0 174 km S of Adak, Alaska
  5. 2.2 188 km S of Adak, Alaska
  6. 2.2 158 km S of Adak, Alaska
  7. 3.8 175 km S of Adak, Alaska
  8. 2.2 183 km SSW of Adak, Alaska
  9. 3.0 202 km S of Adak, Alaska
  10. 2.9 189 km S of Adak, Alaska
  11. 3.1 213 km S of Adak, Alaska
  12. 2.8 171 km S of Adak, Alaska
  13. 3.6 184 km S of Adak, Alaska
  14. 2.1 Andreanof Islands, Aleutian Islands, Alaska
  15. 2.6 175 km S of Adak, 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.