QuakeIndex

Earthquake · reviewed by a seismologist

M 4.3ml

Alaska Peninsula

Yes. A magnitude 4.3 earthquake was recorded in the Alaska Peninsula at 19:54 UTC on 2018-07-01, 52 km deep. 2 people have reported feeling it to USGS.

· 52 km deep · released about 43 tons of TNT

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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 4.3 (ml)
Depth
52 km below the surface
Felt
2 reports · strongest reported intensity III
Measured shaking
intensity III (ShakeMap)
USGS impact alert
green
Nearest
Kodiak Island Borough, 121 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1186 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 109 km (68 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 43 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 4,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 180× the energy of this one
  3. Magna, Utah 2020 M 5.7 130× the energy of this one
  4. This earthquake M 4.3 about 43 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 89× 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 32 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 57.0600, -155.5506. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Kodiak Island Borough, AK 121 km (75 mi) NE earthquakes near Kodiak Island Borough
Lake and Peninsula Borough, AK 127 km (79 mi) NNW earthquakes near Lake and Peninsula Borough

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

Aftershocks so far

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

  1. 2.3 55 km W of Akhiok, Alaska
  2. 1.6 85 km W of Akhiok, Alaska
  3. 2.4 71 km WSW of Karluk, Alaska
  4. 1.7 64 km WSW of Karluk, Alaska
  5. 2.2 93 km W of Akhiok, Alaska
  6. 1.5 57 km WSW of Karluk, Alaska
  7. 1.7 59 km W of Akhiok, Alaska
  8. 1.6 59 km WNW of Akhiok, Alaska
  9. 1.5 54 km W of Akhiok, Alaska
  10. 2.5 62 km W of Akhiok, Alaska
  11. 1.6 61 km WNW of Akhiok, Alaska
  12. 2.2 63 km WSW of Karluk, Alaska
  13. 1.6 64 km WNW of Akhiok, Alaska
  14. 2.3 92 km WSW of Karluk, Alaska
  15. 1.7 71 km SW of Karluk, 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.