QuakeIndex

Earthquake · reviewed by a seismologist

M 4.2mwr

Alaska Peninsula

Yes. A magnitude 4.2 earthquake was recorded in the Alaska Peninsula at 22:47 UTC on 2023-07-02, 13 km deep. 1 person has reported feeling it to USGS.

· 13 km deep · released about 30 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lake and Peninsula Borough 46 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 4.2 (mwr)
Depth
13 km below the surface
Felt
1 report · strongest reported intensity II
Measured shaking
intensity IV (ShakeMap)
Nearest
Lake and Peninsula Borough, 46 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1160 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 112 km (70 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 30 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 5,600× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 250× the energy of this one
  3. Magna, Utah 2020 M 5.7 180× the energy of this one
  4. This earthquake M 4.2 about 30 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 63× 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 in our catalogue was M 5.3 on 2018-05-11 — about 45 times the energy of this one.

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 57.7708, -155.9649. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake and Peninsula Borough, AK 46 km (29 mi) NW earthquakes near Lake and Peninsula Borough
Bristol Bay Borough, AK 123 km (76 mi) NNW earthquakes near Bristol Bay Borough

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

Aftershocks so far

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

  1. 1.7 Alaska Peninsula
  2. 1.5 93 km ESE of Egegik, Alaska
  3. 2.4 92 km ESE of Egegik, Alaska
  4. 1.9 72 km E of Ugashik, Alaska
  5. 2.4 63 km E of Ugashik, Alaska
  6. 1.7 88 km WNW of Karluk, Alaska
  7. 1.9 76 km ENE of Ugashik, Alaska
  8. 2.4 89 km WNW of Karluk, Alaska
  9. 2.0 91 km WNW of Karluk, Alaska
  10. 1.9 88 km WNW of Karluk, Alaska
  11. 2.1 92 km WNW of Karluk, Alaska
  12. 2.1 89 km WNW of Karluk, Alaska
  13. 1.5 91 km WNW of Karluk, Alaska
  14. 2.0 58 km ENE of Ugashik, Alaska
  15. 2.0 72 km SE 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.