QuakeIndex

Earthquake · automatic estimate, may change

M 2.3ml

Earthquake near Butte, AK

No earthquake was likely felt in Butte in the 24 hours to 3:46 am AKST (12:46 UTC). The last one was M 4.4, 112 km (69 mi) ENE, at 11:11 am AKDT on 30 October 2026, estimated intensity II (weak) in town; 54 felt reports to USGS. Every earthquake near Butte

This page: a magnitude 2.3 earthquake was recorded 47 km (29 mi) east of Butte, AK, at 3:10 pm AKDT on 22 July 2020 (23:10 UTC), 239 km deep. The magnitude and location are an automatic first estimate and may change.

USGS: 30 km SSE of Chickaloon, Alaska

3:10 pm AKDT, Jul 22, 2020 · · 239 km deep · released about 85 lb of TNT

Every earthquake near Butte Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 75 kmMatanuska-Susitna Borough 105 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
3:10 pm AKDT on 22 July 2020 ()
Where
47 km (29 mi) east of Butte, AK · earthquakes near Butte
Magnitude
M 2.3 (ml)
Depth
239 km below the surface
Felt
no reports yet
Nearest
Anchorage Municipality, 75 km SW
Status
Automatic — a machine’s first estimate, which may change

USGS · last changed by USGS · we first saw it 2292 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 Butte, 47 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.

How big was it?

This earthquake released about 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
  3. Around the size people start to feel M 3.0 11× the energy of this one
  4. This earthquake M 2.3 about 85 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 4.6 on 2018-01-27 — about 2,800 times the energy of this one.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 31 km SSW of Glacier View, Alaska · 19 km ESE of this epicentre
  2. 6.4 23 km S of Glacier View, Alaska · 26 km E of this epicentre
  3. 6.4 37 km SSE of Glacier View, Alaska · 40 km ESE of this epicentre
  4. 5.9 15 km N of Glacier View, Alaska · 48 km NNE of this epicentre
  5. 5.9 42 km S of Glacier View, Alaska · 33 km ESE 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 61.5687, -148.1436. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 75 km (47 mi) SW earthquakes near Anchorage Municipality
Matanuska-Susitna Borough, AK 105 km (65 mi) NW earthquakes near Matanuska-Susitna Borough

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

Aftershocks so far

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

  1. 2.4 4 km NE of Chickaloon, Alaska
  2. 1.9 28 km SSE of Chickaloon, Alaska
  3. 1.9 30 km SSE of Chickaloon, Alaska
  4. 1.9 33 km SSE of Chickaloon, Alaska
  5. 2.3 31 km SSE of Chickaloon, Alaska
  6. 2.1 33 km SSE of Chickaloon, Alaska
  7. 2.1 31 km SSE of Chickaloon, Alaska
  8. 1.6 20 km SE of Chickaloon, Alaska
  9. 1.8 15 km S of Chickaloon, Alaska
  10. 1.8 16 km E of Lazy Mountain, Alaska
  11. 1.6 65 km WNW of Tatitlek, Alaska
  12. 1.5 31 km SSE of Chickaloon, Alaska
  13. 2.4 31 km SSE of Chickaloon, Alaska
  14. 1.6 15 km ESE of Chickaloon, Alaska
  15. 1.9 32 km SSW of Glacier View, 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.