QuakeIndex

Earthquake · reviewed by a seismologist

M 4.7mw

7 km SW of Knik, Alaska

· 41 km deep · released about 170 tons of TNT

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10 km30 km60 km120 km N Anchorage Municipality 40 kmMatanuska-Susitna Borough 96 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 4.7 (mw)
Depth
41 km below the surface
Felt
596 reports · strongest reported intensity V
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Anchorage Municipality, 40 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1137 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 596 people have reported feeling it to USGS.

How big was it?

This earthquake released about 170 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.7 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 1,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 45× the energy of this one
  3. Magna, Utah 2020 M 5.7 32× the energy of this one
  4. This earthquake M 4.7 about 170 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 350× 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.

Where

Epicentre 61.4201, -149.8368. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Anchorage Municipality, AK 40 km (25 mi) NW of here earthquakes near Anchorage Municipality
Matanuska-Susitna Borough, AK 96 km (59 mi) S of here earthquakes near Matanuska-Susitna Borough

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

Aftershocks so far

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

  1. 1.5 6 km S of Big Lake, Alaska
  2. 1.5 8 km NNW of Point MacKenzie, Alaska
  3. 1.5 5 km S of Big Lake, Alaska
  4. 2.7 3 km WNW of Point MacKenzie, Alaska
  5. 1.6 6 km WNW of Point MacKenzie, Alaska
  6. 1.8 4 km WNW of Point MacKenzie, Alaska
  7. 1.6 2 km NE of Big Lake, Alaska
  8. 1.6 2 km SSW of Big Lake, Alaska
  9. 2.1 3 km N of Big Lake, Alaska
  10. 2.3 3 km NW of Point MacKenzie, Alaska
  11. 1.6 4 km SSE of Big Lake, Alaska
  12. 2.2 8 km WSW of Knik, Alaska
  13. 1.6 7 km SSE of Big Lake, Alaska
  14. 1.8 3 km WNW of Big Lake, Alaska
  15. 1.5 2 km NW of Point MacKenzie, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 7.1 on 2018-11-30 — it released about 4,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.