QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

72 km SSW of Sand Point, Alaska

Yes. A magnitude 1.6 earthquake was recorded 72 km SSW of Sand Point, Alaska, at 10:45 am AKDT on 4 August 2020 (18:45 UTC), 26 km deep.

· 26 km deep · released about 7.6 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aleutians East Borough 101 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 1.6 (ml)
Depth
26 km below the surface
Felt
no reports yet
Nearest
Aleutians East Borough, 101 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2277 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. 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 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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 6.1 on 2020-07-28 — about 5,600,000 times the energy of this one.

Before 2016, the USGS record lists 42 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.1 90 km SE of King Cove, Alaska · 30 km WSW of this epicentre
  2. 6.8 73 km SW of Sand Point, Alaska · 34 km WNW of this epicentre
  3. 6.4 101 km SSW of Sand Point, Alaska · 32 km SW of this epicentre
  4. 6.4 85 km ESE of King Cove, Alaska · 29 km W of this epicentre
  5. 6.2 35 km S of Sand Point, Alaska · 38 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 54.7002, -160.7392. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aleutians East Borough, AK 101 km (63 mi) NW earthquakes near Aleutians East 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. 2.4 91 km SE of King Cove, Alaska
  2. 2.6 57 km S of Sand Point, Alaska
  3. 2.3 94 km SE of King Cove, Alaska
  4. 3.0 82 km ESE of King Cove, Alaska
  5. 3.0 102 km SSW of Sand Point, Alaska
  6. 2.8 102 km SE of King Cove, Alaska
  7. 3.1 106 km SE of King Cove, Alaska
  8. 3.5 108 km SE of King Cove, Alaska
  9. 3.9 92 km SE of King Cove, Alaska
  10. 3.1 100 km SE of King Cove, Alaska
  11. 2.2 53 km S of Sand Point, Alaska
  12. 2.7 85 km SSW of Sand Point, Alaska
  13. 3.2 112 km S of Sand Point, Alaska
  14. 1.9 81 km ESE of King Cove, Alaska
  15. 1.7 78 km ESE of King Cove, 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.