QuakeIndex

Earthquake · reviewed by a seismologist

M 4.3ml

Earthquake near Valdez, AK

No earthquake was likely felt in Valdez in the 24 hours to 4:10 am AKST (13:10 UTC). The last one was M 4.4, 85 km (53 mi) NNW, at 11:11 am AKDT on 30 October 2026, estimated intensity II (weak) in town; 54 felt reports to USGS. Every earthquake near Valdez

This page: a magnitude 4.3 earthquake was recorded 45 km (28 mi) north of Valdez, AK, at 3:22 am AKDT on 16 October 2018 (11:22 UTC), 30 km deep. 12 people have reported feeling it to USGS.

USGS: 45 km N of Valdez, Alaska

3:22 am AKDT, Oct 16, 2018 · · 30 km deep · released about 43 tons of TNT

Every earthquake near Valdez Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Chugach Census Area 117 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
3:22 am AKDT on 16 October 2018 ()
Where
45 km (28 mi) north of Valdez, AK · earthquakes near Valdez
Magnitude
M 4.3 (ml)
Depth
30 km below the surface
Felt
12 reports · strongest reported intensity III
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Chugach Census Area, 117 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1185 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 117 km (73 mi) from the epicentre. In Valdez, 45 km away, the estimate is intensity III (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.

Likely felt in: Valdez 45 km, intensity III. Estimated for each town centre; each link is that town's own record.

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

Tied for the largest within 50 km (31 mi) since 2016, with M 4.3 on 2016-08-19.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

  1. 5.5 47 km SSE of Glacier View, Alaska · 50 km WSW of this epicentre
  2. 5.5 48 km WNW of Valdez, Alaska · 43 km WSW of this epicentre
  3. 5.3 49 km WNW of Valdez, Alaska · 47 km WSW of this epicentre
  4. 5.1 48 km NNW of Valdez, Alaska · 13 km W of this epicentre
  5. 5.1 48 km SSE of Nelchina, Alaska · 6 km N 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 61.5360, -146.3975. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Chugach Census Area, AK 117 km (73 mi) S earthquakes near Chugach Census Area

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. 1.7 39 km N of Valdez, Alaska
  2. 1.7 10 km NW of Valdez, Alaska
  3. 1.9 48 km N of Valdez, Alaska
  4. 1.6 46 km S of Nelchina, Alaska
  5. 1.5 47 km N of Valdez, Alaska
  6. 1.5 33 km SSE of Eureka Roadhouse, Alaska
  7. 1.5 48 km SSE of Nelchina, Alaska
  8. 1.7 36 km NNW of Valdez, Alaska
  9. 1.8 48 km N of Valdez, Alaska
  10. 3.0 48 km N of Valdez, Alaska
  11. 1.6 49 km N of Valdez, Alaska
  12. 1.8 49 km N of Valdez, Alaska
  13. 2.3 46 km N of Valdez, Alaska
  14. 1.6 46 km N of Valdez, Alaska
  15. 1.6 47 km N of Valdez, 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.