QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9mwr

Oklahoma

Yes. A magnitude 3.9 earthquake was recorded in Oklahoma, 83 km (51 mi) N of Oklahoma City, OK, at 4:46 pm CDT on 9 August 2016 (21:46 UTC), 6.6 km deep. 207 people have reported feeling it to USGS.

83 km (51 mi) N of Oklahoma City, OK · 35 km (21 mi) SE of Enid, OK

· 6.6 km deep · released about 11 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Garfield County 27 kmLogan County 35 kmNoble County 36 kmKingfisher County 44 kmPayne County 55 kmGrant County 67 kmOklahoma County 74 kmKay County 77 kmPawnee County 79 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
Oklahoma today
every earthquake in Oklahoma in the last 24 hours
Magnitude
M 3.9 (mwr)
Depth
6.6 km below the surface
Felt
207 reports · strongest reported intensity IV
Measured shaking
intensity V (ShakeMap)
Nearest
Garfield County, 27 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2428 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 431 km (268 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.

Likely felt in: Perry 27 km, intensity IV · Crescent 29 km, intensity IV · Hennessey 32 km, intensity IV · Enid 34 km, intensity IV · Guthrie 39 km, intensity III · Langston 41 km, intensity III · Stillwater 47 km, intensity III. Estimated for each town centre; each link is that town's own record.

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.

For this area

The largest earthquake within 50 km since 2016 was M 4.2 on 2016-03-29 — about 2.8 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 36.2110, -97.5700. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Garfield County, OK 27 km (17 mi) NW earthquakes near Garfield County
Logan County, OK 35 km (22 mi) SSE earthquakes near Logan County
Noble County, OK 36 km (22 mi) ENE earthquakes near Noble County
Kingfisher County, OK 44 km (27 mi) SW earthquakes near Kingfisher County
Payne County, OK 55 km (34 mi) ESE earthquakes near Payne County
Grant County, OK 67 km (42 mi) NNW earthquakes near Grant 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. 2.6 9 km ENE of Mulhall, Oklahoma
  2. 2.9 8 km NE of Marshall, Oklahoma
  3. 2.6 0 km E of Coyle, Oklahoma
  4. 2.7 6 km NNE of Stillwater, Oklahoma
  5. 2.7 6 km NNE of Stillwater, Oklahoma
  6. 2.8 6 km NNE of Stillwater, Oklahoma
  7. 1.9 1 km NNE of Red Rock, Oklahoma
  8. 3.0 11 km N of Perry, Oklahoma
  9. 2.5 5 km N of Stillwater, Oklahoma
  10. 3.1 5 km N of Stillwater, Oklahoma
  11. 3.2 5 km N of Stillwater, Oklahoma
  12. 3.3 4 km WNW of Lucien, Oklahoma
  13. 2.9 11 km N of Perry, Oklahoma
  14. 2.8 4 km NW of Mulhall, Oklahoma
  15. 2.6 3 km WNW of Fairmont, 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.

On USGS

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