QuakeIndex

Earthquake · reviewed by a seismologist

M 3.8ml

Earthquake near Houston, AK

No earthquake was likely felt in Houston in the 24 hours to 12:24 pm AKST (21:24 UTC). The last one was M 2.8, 13 km (8 mi) WSW, at 6:17 am AKST on 6 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Houston

This page: a magnitude 3.8 earthquake was recorded 5 km (3 mi) south-southwest of Houston, AK, at 9:10 am AKST on 30 November 2018 (18:10 UTC), 50 km deep.

USGS: 5 km SSW of Houston, Alaska

41 km (25 mi) N of Anchorage, AK

9:10 am AKST, Nov 30, 2018 · · 50 km deep · released about 7.6 tons of TNT

Every earthquake near Houston Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 54 kmMatanuska-Susitna Borough 78 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
9:10 am AKST on 30 November 2018 ()
Where
5 km (3 mi) south-southwest of Houston, AK · earthquakes near Houston
Magnitude
M 3.8 (ml)
Depth
50 km below the surface
Felt
no reports yet
Measured shaking
intensity III (ShakeMap)
Nearest
Anchorage Municipality, 54 km SSE
Nearest mapped fault
Castle Mountain fault, 3 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1183 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 66 km (41 mi) from the epicentre. In Houston, 5 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.

Likely felt in: Big Lake 9 km, intensity II · Knik-Fairview 15 km, intensity II · Willow 21 km, intensity II · Tanaina 22 km, intensity II · Eagle River 33 km, intensity II · Fishhook 36 km, intensity II · Palmer 38 km, intensity II · Anchorage 41 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 7.6 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.8 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 22,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 1,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 710× the energy of this one
  4. This earthquake M 3.8 about 7.6 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 16× 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 since 2016 was M 7.1 on 2018-11-30 — about 89,000 times the energy of this one.

Before 2016, the USGS record lists 22 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.9 23 km NE of Willow, Alaska · 36 km N of this epicentre
  2. 5.8 14 km NNE of Fishhook, Alaska · 49 km NE of this epicentre
  3. 5.6 11 km NW of Big Lake, Alaska · 15 km W of this epicentre
  4. 5.6 5 km N of Susitna, Alaska · 36 km W of this epicentre
  5. 5.5 2 km ENE of Eagle River, Alaska · 33 km SSE 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 61.5849, -149.8374. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 54 km (34 mi) SSE earthquakes near Anchorage Municipality
Matanuska-Susitna Borough, AK 78 km (48 mi) NNE 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. 2.4 7 km NW of Point MacKenzie, Alaska
  2. 3.2 11 km NW of Point MacKenzie, Alaska
  3. 3.1 7 km NNW of Anchorage, Alaska
  4. 2.8 1 km N of Knik, Alaska
  5. 2.7 2 km NW of Point MacKenzie, Alaska
  6. 2.6 7 km NNE of Point MacKenzie, Alaska
  7. 2.8 3 km SSE of Big Lake, Alaska
  8. 3.0 5 km S of Big Lake, Alaska
  9. 3.4 6 km SSE of Big Lake, Alaska
  10. 3.2 8 km NNE of Point MacKenzie, Alaska
  11. 3.1 2 km SSW of Big Lake, Alaska
  12. 2.8 6 km SSE of Point MacKenzie, Alaska
  13. 2.3 7 km SSE of Big Lake, Alaska
  14. 3.4 5 km SSE of Big Lake, Alaska
  15. 2.7 1 km S of Big Lake, 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.