QuakeIndex

Earthquake · reviewed by a seismologist

M 5.1mw

24 km ENE of Tanana, Alaska

Yes. A magnitude 5.1 earthquake was recorded 24 km ENE of Tanana, Alaska at 16:57 UTC on 2018-10-27, 15 km deep. 47 people have reported feeling it to USGS.

· 15 km deep · released about 670 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Yukon-Koyukuk Census Area 16 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 5.1 (mw)
Depth
15 km below the surface
Felt
47 reports · strongest reported intensity III
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Nearest
Yukon-Koyukuk Census Area, 16 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1184 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

At this magnitude and depth, people at rest would likely notice it out to about 205 km (127 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 670 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11× the energy of this one
  3. Magna, Utah 2020 M 5.7 7.9× the energy of this one
  4. This earthquake M 5.1 about 670 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 1,400× 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 (31 mi) since our catalogue begins in 2016. The previous largest was M 4.2 on 2016-05-18.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.9 15 km SSE of Tanana, Alaska · 26 km SW of this epicentre
  2. 5.9 31 km SSE of Tanana, Alaska · 40 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 65.2283, -151.5744. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Yukon-Koyukuk Census Area, AK 16 km (10 mi) N earthquakes near Yukon-Koyukuk Census Area

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. 1.9 12 km ENE of Tanana, Alaska
  2. 1.7 41 km WSW of Manley Hot Springs, Alaska
  3. 1.6 37 km SE of Tanana, Alaska
  4. 1.5 25 km SSE of Tanana, Alaska
  5. 1.5 19 km W of Manley Hot Springs, Alaska
  6. 1.5 20 km W of Manley Hot Springs, Alaska
  7. 3.2 31 km SE of Tanana, Alaska
  8. 1.5 33 km SSE of Tanana, Alaska
  9. 1.7 36 km S of Tanana, Alaska
  10. 2.5 northern Alaska
  11. 1.5 Central Alaska
  12. 1.6 9 km SSE of Tanana, Alaska
  13. 2.4 43 km N of Tanana, Alaska
  14. 1.7 36 km WSW of Manley Hot Springs, Alaska
  15. 1.5 27 km WSW of Manley Hot Springs, 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.