QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Big Lake, AK

No earthquake was likely felt in Big Lake in the 24 hours to 1:36 pm AKST (22:36 UTC). The last one was M 2.8, 6 km (4 mi) NW, at 6:17 am AKST on 6 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Big Lake

This page: a magnitude 1.6 earthquake was recorded 2 km (1 mi) east-northeast of Big Lake, AK, at 3:28 pm AKDT on 1 October 2019 (23:28 UTC), 40 km deep.

USGS: 2 km ENE of Big Lake, Alaska

34 km (21 mi) N of Anchorage, AK

3:28 pm AKDT, Oct 1, 2019 · · 40 km deep · released about 7.6 lb of TNT

Every earthquake near Big Lake Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 52 kmMatanuska-Susitna Borough 85 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
3:28 pm AKDT on 1 October 2019 ()
Where
2 km (1 mi) east-northeast of Big Lake, AK · earthquakes near Big Lake
Magnitude
M 1.6 (ml)
Depth
40 km below the surface
Felt
no reports yet
Nearest
Anchorage Municipality, 52 km SE
Nearest mapped fault
Castle Mountain fault, 8 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 2526 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. In Big Lake, 2 km away, the estimate is intensity I (not felt). 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.

Earthquakes near other towns within 30 km: Houston, Knik-Fairview, Meadow Lakes, Willow, Wasilla, Tanaina.

How big was it?

This earthquake released about 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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

The largest earthquake within 50 km since 2016 was M 7.1 on 2018-11-30 — about 180,000,000 times the energy of this one.

Before 2016, the USGS record lists 19 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.9 23 km NE of Willow, Alaska · 44 km NNE of this epicentre
  2. 5.6 11 km NW of Big Lake, Alaska · 13 km WNW of this epicentre
  3. 5.6 5 km N of Susitna, Alaska · 32 km WNW of this epicentre
  4. 5.5 2 km ENE of Eagle River, Alaska · 30 km SE of this epicentre
  5. 5.5 9 km E of Susitna, Alaska · 22 km W 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 61.5264, -149.9179. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 52 km (32 mi) SE earthquakes near Anchorage Municipality
Matanuska-Susitna Borough, AK 85 km (53 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. 2.0 5 km NW of Point MacKenzie, Alaska
  2. 2.1 5 km N of Point MacKenzie, Alaska
  3. 1.7 1 km W of Point MacKenzie, Alaska
  4. 1.8 6 km WNW of Point MacKenzie, Alaska
  5. 1.7 2 km WNW of Point MacKenzie, Alaska
  6. 2.8 14 km SW of Willow, Alaska
  7. 2.3 Southern Alaska
  8. 1.9 13 km NNE of Houston, Alaska
  9. 1.8 9 km SW of Willow, Alaska
  10. 1.5 3 km S of Big Lake, Alaska
  11. 1.8 6 km WNW of Houston, Alaska
  12. 1.8 7 km NW of Elmendorf Air Force Base, Alaska
  13. 1.6 8 km NNE of Willow, Alaska
  14. 1.7 4 km SSE of Big Lake, Alaska
  15. 2.3 2 km SSE 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.