QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Colorado

Yes. A magnitude 1.6 earthquake was recorded in Colorado, at 10:39 pm MDT on 20 September 2023 (04:39 UTC), 6.1 km deep.

· 6.1 km deep · released about 7.6 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Las Animas County 40 kmHuerfano County 59 kmColfax County 78 kmCostilla County 83 kmOtero County 93 kmPueblo County 95 kmCuster County 118 kmAlamosa County 118 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 1.6 (ml)
Depth
6.1 km below the surface
Felt
no reports yet
Nearest
Las Animas County, 40 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1075 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 4 km (2 mi) from the epicentre. 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: Trinidad.

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 4.3 on 2023-03-10 — about 11,000 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.3 6 km S of Valdez, Colorado · 33 km SW 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 37.3078, -104.4908. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Las Animas County, CO 40 km (25 mi) E earthquakes near Las Animas County
Huerfano County, CO 59 km (37 mi) NW earthquakes near Huerfano County
Colfax County, NM 78 km (49 mi) S earthquakes near Colfax County
Costilla County, CO 83 km (52 mi) W earthquakes near Costilla County
Otero County, CO 93 km (58 mi) NE earthquakes near Otero County
Pueblo County, CO 95 km (59 mi) N earthquakes near Pueblo County

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

Aftershocks so far

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

  1. 2.5 6 km NNW of El Moro, Colorado
  2. 1.6 9 km NNW of El Moro, Colorado
  3. 1.5 9 km NNW of El Moro, Colorado
  4. 2.1 8 km N of El Moro, Colorado
  5. 2.5 8 km NNW of El Moro, Colorado
  6. 1.6 10 km WNW of Hoehne, Colorado
  7. 1.5 8 km NNW of El Moro, Colorado
  8. 2.4 8 km NNW of El Moro, Colorado
  9. 2.9 8 km NNW of El Moro, Colorado
  10. 1.7 6 km N of Hoehne, Colorado
  11. 1.6 6 km NNW of Hoehne, Colorado
  12. 1.7 8 km NNE of Weston, Colorado
  13. 1.7 8 km N of Valdez, Colorado
  14. 1.9 42 km NE of Hoehne, Colorado
  15. 1.9 11 km SE of Stonewall Gap, Colorado

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.