QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

8 km WSW of Helena, Oklahoma

· 6.6 km deep · released about 1,300 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alfalfa County 23 kmMajor County 29 kmWoods County 51 kmGarfield County 53 kmGrant County 59 kmBlaine County 72 kmKingfisher County 74 kmHarper County 78 kmWoodward County 83 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 3.1 (ml)
Depth
6.6 km below the surface
Felt
no reports yet
Nearest
Alfalfa County, 23 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3542 days ago

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

How big was it?

This earthquake released about 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× 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 36.5225, -98.3547. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alfalfa County, OK 23 km (14 mi) S of here earthquakes near Alfalfa County
Major County, OK 29 km (18 mi) NE of here earthquakes near Major County
Woods County, OK 51 km (32 mi) ESE of here earthquakes near Woods County
Garfield County, OK 53 km (33 mi) WNW of here earthquakes near Garfield County
Grant County, OK 59 km (36 mi) WSW of here earthquakes near Grant County
Blaine County, OK 72 km (45 mi) N of here earthquakes near Blaine County

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

Aftershocks so far

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

  1. 2.9 17 km SE of Waynoka, Oklahoma
  2. 2.5 12 km WSW of Cleo Springs, Oklahoma
  3. 2.7 16 km SE of Waynoka, Oklahoma
  4. 2.7 5 km N of Lambert, Oklahoma
  5. 2.6 16 km SSE of Waynoka, Oklahoma
  6. 3.0 17 km SSE of Waynoka, Oklahoma
  7. 2.6 17 km SSE of Waynoka, Oklahoma
  8. 3.0 17 km SSE of Waynoka, Oklahoma
  9. 2.9 17 km SSE of Waynoka, Oklahoma
  10. 2.9 17 km SSE of Waynoka, Oklahoma
  11. 2.5 4 km NNE of Lambert, Oklahoma
  12. 2.6 4 km NNE of Cherokee, Oklahoma
  13. 2.5 16 km SSE of Waynoka, Oklahoma
  14. 3.0 16 km SSE of Waynoka, Oklahoma
  15. 2.5 6 km E of Nescatunga, Oklahoma

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 5.1 on 2016-02-13 — it released about 1,000 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.