QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9ml

65 km SE of King Salmon, Alaska

Yes. A magnitude 3.9 earthquake was recorded 65 km SE of King Salmon, Alaska at 14:57 UTC on 2020-02-02, 147 km deep.

· 147 km deep · released about 11 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lake and Peninsula Borough 29 kmBristol Bay Borough 82 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
Magnitude
M 3.9 (ml)
Depth
147 km below the surface
Felt
no reports yet
Nearest
Lake and Peninsula Borough, 29 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2399 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 11 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 16,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 710× the energy of this one
  3. Magna, Utah 2020 M 5.7 500× the energy of this one
  4. This earthquake M 3.9 about 11 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 22× 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 5.5 on 2016-07-23 — about 250 times the energy of this one.

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

  1. 6.8 Event 48 Novarupta-Mount Katmai area, Alaska Peninsula · 46 km E of this epicentre
  2. 6.6 19 km SSE of King Salmon, Alaska · 47 km NW of this epicentre
  3. 5.3 37 km S of King Salmon, Alaska · 43 km WNW of this epicentre
  4. 5.2 67 km ESE of Egegik, Alaska · 44 km SW 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 58.2184, -155.9737. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake and Peninsula Borough, AK 29 km (18 mi) WSW earthquakes near Lake and Peninsula Borough
Bristol Bay Borough, AK 82 km (51 mi) NW earthquakes near Bristol Bay Borough

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

Aftershocks so far

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

  1. 2.5 47 km SE of King Salmon, Alaska
  2. 1.5 65 km ESE of King Salmon, Alaska
  3. 1.8 77 km ENE of Ugashik, Alaska
  4. 1.7 57 km ESE of Egegik, Alaska
  5. 1.5 74 km ENE of Ugashik, Alaska
  6. 2.7 77 km SE of King Salmon, Alaska
  7. 1.6 76 km ESE of Egegik, Alaska
  8. 2.4 62 km SE of King Salmon, Alaska
  9. 1.8 59 km ESE of King Salmon, Alaska
  10. 1.6 53 km SE of King Salmon, Alaska
  11. 2.0 82 km ESE of Egegik, Alaska
  12. 1.7 74 km ESE of Egegik, Alaska
  13. 1.7 57 km SE of King Salmon, Alaska
  14. 1.9 63 km ESE of Egegik, Alaska
  15. 2.5 51 km ESE of King Salmon, 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.