QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9mwr

18 km SSW of Weston, CO

· 3.6 km deep · released about 11 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Colfax County 50 kmCostilla County 54 kmTaos County 77 kmHuerfano County 78 kmLas Animas County 88 kmAlamosa County 99 kmMora County 112 kmConejos County 112 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 3.9 (mwr)
Depth
3.6 km below the surface
Felt
10 reports · strongest reported intensity III
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Nearest
Colfax County, 50 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3599 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 10 people have reported feeling it to USGS.

How big was it?

This earthquake released about 11 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 16,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 710× the energy of this one
  3. Magna, Utah 2020 M 5.7 500× the energy of this one
  4. This earthquake M 3.9 about 11 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 22× 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.

Where

Epicentre 36.9863, -104.9449. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Colfax County, NM 50 km (31 mi) NNW of here earthquakes near Colfax County
Costilla County, CO 54 km (33 mi) SE of here earthquakes near Costilla County
Taos County, NM 77 km (48 mi) NE of here earthquakes near Taos County
Huerfano County, CO 78 km (48 mi) S of here earthquakes near Huerfano County
Las Animas County, CO 88 km (55 mi) WSW of here earthquakes near Las Animas County
Alamosa County, CO 99 km (61 mi) SE of here earthquakes near Alamosa County

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

Aftershocks so far

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

  1. 1.7 14 km SSE of Stonewall Gap, Colorado
  2. 2.1 16 km SSE of Stonewall Gap, Colorado
  3. 2.8 16 km SSE of Stonewall Gap, Colorado
  4. 1.6 15 km SSE of Stonewall Gap, Colorado
  5. 3.1 15 km SSE of Stonewall Gap, Colorado
  6. 1.5 13 km SSE of Stonewall Gap, Colorado
  7. 3.8 15 km SSE of Stonewall Gap, Colorado
  8. 1.7 6 km WNW of El Moro, Colorado
  9. 2.1 17 km SSE of Stonewall Gap, Colorado
  10. 1.5 5 km SSW of Weston, Colorado
  11. 2.0 12 km SW of Weston, Colorado
  12. 1.5 11 km SW of Weston, Colorado
  13. 2.7 31 km SSW of Weston, Colorado
  14. 1.8 14 km SSW of Aguilar, Colorado
  15. 1.5 15 km SW of Aguilar, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.0 on 2016-02-06 — it released about 1.4 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.