QuakeIndex

Earthquake · reviewed by a seismologist

M 3.8mb_lg

9 km SSW of Helena, Oklahoma

· 5.0 km deep · released about 7.6 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Major County 27 kmAlfalfa County 30 kmGarfield County 47 kmWoods County 58 kmGrant County 58 kmKingfisher County 66 kmBlaine County 66 kmHarper County 83 kmDewey County 84 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 3.8 (mb_lg)
Depth
5.0 km below the surface
Felt
no reports yet
Measured shaking
intensity IV (ShakeMap)
Nearest
Major County, 27 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3537 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 7.6 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.8 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 22,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 1,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 710× the energy of this one
  4. This earthquake M 3.8 about 7.6 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 16× 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 36.4642, -98.3036. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Major County, OK 27 km (17 mi) NE of here earthquakes near Major County
Alfalfa County, OK 30 km (18 mi) S of here earthquakes near Alfalfa County
Garfield County, OK 47 km (29 mi) WNW of here earthquakes near Garfield County
Woods County, OK 58 km (36 mi) ESE of here earthquakes near Woods County
Grant County, OK 58 km (36 mi) SW of here earthquakes near Grant County
Kingfisher County, OK 66 km (41 mi) NNW of here earthquakes near Kingfisher County

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. 2.6 4 km SW of Cherokee, Oklahoma
  2. 2.5 17 km SSE of Waynoka, Oklahoma
  3. 2.5 17 km SE of Waynoka, Oklahoma
  4. 2.5 17 km SSE of Waynoka, Oklahoma
  5. 2.5 17 km SSE of Waynoka, Oklahoma
  6. 2.9 17 km SSE of Waynoka, Oklahoma
  7. 2.8 17 km SSE of Waynoka, Oklahoma
  8. 2.7 4 km NE of Meno, Oklahoma
  9. 2.7 17 km SSE of Waynoka, Oklahoma
  10. 2.9 17 km SE of Waynoka, Oklahoma
  11. 2.5 12 km WSW of Cleo Springs, Oklahoma
  12. 2.7 16 km SE of Waynoka, Oklahoma
  13. 2.7 5 km N of Lambert, Oklahoma
  14. 2.6 16 km SSE of Waynoka, Oklahoma
  15. 3.0 17 km SSE of Waynoka, 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 89 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.