QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Dutch Harbor, AK

No earthquake was likely felt in Dutch Harbor in the 24 hours to 10:21 pm AKST (07:21 UTC). The last one was M 4.4, 117 km (73 mi) ESE, at 3:00 pm AKST on 11 November 2026, estimated intensity II (weak) in town. Every earthquake near Dutch Harbor

This page: a magnitude 1.8 earthquake was recorded 17 km (11 mi) west of Dutch Harbor, AK, at 10:20 pm AKDT on 24 July 2018 (06:20 UTC), 8.2 km deep.

USGS: 17 km W of Dutch Harbor, Alaska

10:20 pm AKDT, Jul 24, 2018 · · 8.2 km deep · released about 13 lb 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
10:20 pm AKDT on 24 July 2018 ()
Where
17 km (11 mi) west of Dutch Harbor, AK · earthquakes near Dutch Harbor
Magnitude
M 1.8 (ml)
Depth
8.2 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2809 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 10 km (6 mi) from the epicentre. In Dutch Harbor, 17 km away, the estimate is intensity II (weak). 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.

Earthquakes near other towns within 30 km: Unalaska.

How big was it?

This earthquake released about 13 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 840,000× the energy of this one
  3. Around the size people start to feel M 3.0 75× the energy of this one
  4. This earthquake M 1.8 about 13 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 4.0 on 2016-08-29 — about 2,400 times the energy of this one.

Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.0 51 km SW of Unalaska, Alaska · 38 km SW of this epicentre
  2. 5.9 27 km WNW of Dutch Harbor, Alaska · 16 km NNW of this epicentre
  3. 5.9 13 km NE of Dutch Harbor, Alaska · 29 km ENE of this epicentre
  4. 5.4 48 km WSW of Unalaska, Alaska · 32 km WSW of this epicentre
  5. 5.4 26 km WSW of Dutch Harbor, Alaska · 9 km WSW 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 53.8635, -166.8018. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.5 52 km SW of Unalaska, Alaska
  2. 1.8 48 km SSW of Unalaska, Alaska
  3. 1.9 35 km WSW of Unalaska, Alaska
  4. 1.9 Fox Islands, Aleutian Islands, Alaska
  5. 1.6 57 km SSW of Unalaska, Alaska
  6. 1.5 10 km SE of Unalaska, Alaska
  7. 2.2 61 km WSW of Unalaska, Alaska
  8. 3.2 62 km SW of Unalaska, Alaska
  9. 2.8 32 km S of Unalaska, Alaska
  10. 2.4 51 km SW of Unalaska, Alaska
  11. 2.3 42 km SW of Unalaska, Alaska
  12. 1.7 8 km SW of Unalaska, Alaska
  13. 2.0 53 km SW of Unalaska, Alaska
  14. 1.5 11 km SW of Unalaska, Alaska
  15. 1.5 11 km SSW of Unalaska, 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.