QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

16 km SSW of Eureka Roadhouse, Alaska

Yes. A magnitude 1.5 earthquake was recorded 16 km SSW of Eureka Roadhouse, Alaska, at 3:04 pm AKDT on 26 September 2020 (23:04 UTC), 36 km deep.

· 36 km deep · released about 5.4 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
Magnitude
M 1.5 (ml)
Depth
36 km below the surface
Felt
no reports yet
Nearest
Matanuska-Susitna Borough, 128 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2229 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 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 180× the energy of this one
  4. This earthquake M 1.5 about 5.4 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 31 km SSW of Glacier View, Alaska · 41 km SW of this epicentre
  2. 6.4 23 km S of Glacier View, Alaska · 31 km SW of this epicentre
  3. 6.4 37 km SSE of Glacier View, Alaska · 35 km SSW of this epicentre
  4. 5.9 15 km N of Glacier View, Alaska · 28 km NW of this epicentre
  5. 5.9 42 km S of Glacier View, Alaska · 45 km SSW 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 61.8013, -147.2612. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Matanuska-Susitna Borough, AK 128 km (79 mi) WNW earthquakes near Matanuska-Susitna Borough
Anchorage Municipality, AK 128 km (80 mi) WSW earthquakes near Anchorage Municipality

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

Aftershocks so far

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

  1. 1.5 35 km SE of Glacier View, Alaska
  2. 1.6 44 km SSE of Eureka Roadhouse, Alaska
  3. 2.0 47 km SSE of Glacier View, Alaska
  4. 2.3 8 km NW of Glacier View, Alaska
  5. 1.9 30 km SE of Glacier View, Alaska
  6. 2.6 20 km S of Glacier View, Alaska
  7. 2.5 12 km WSW of Eureka Roadhouse, Alaska
  8. 1.8 16 km NNW of Glacier View, Alaska
  9. 2.0 18 km ESE of Glacier View, Alaska
  10. 1.5 19 km S of Nelchina, Alaska
  11. 1.8 30 km S of Nelchina, Alaska
  12. 1.8 42 km S of Glacier View, Alaska
  13. 1.7 49 km SSE of Glacier View, Alaska
  14. 2.1 39 km NNW of Valdez, Alaska
  15. 2.1 40 km NNW of Glacier View, 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.