QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

Earthquake near Blackwell, OK

No earthquake was likely felt in Blackwell in the 24 hours to 3:49 pm CST (21:49 UTC). The last one was M 3.4, 149 km (93 mi) SSW, at 5:53 am CST on 7 November 2026, estimated intensity II (weak) in town; 23 felt reports to USGS. Every earthquake near Blackwell

This page: a magnitude 2.8 earthquake was recorded 37 km (23 mi) west of Blackwell, OK, at 5:26 pm CST on 18 November 2016 (23:26 UTC), 8.0 km deep.

USGS: 5 km NE of Medford, Oklahoma

99 km (61 mi) SSW of Wichita, KS · 51 km (32 mi) NNE of Enid, OK

5:26 pm CST, Nov 18, 2016 · · 8.0 km deep · released about 480 lb of TNT

10 km30 km60 km120 km N Grant County 10 kmSumner County 47 kmKay County 50 kmHarper County 50 kmGarfield County 53 kmAlfalfa County 57 kmNoble County 66 kmCowley County 88 kmKingman County 88 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
5:26 pm CST on 18 November 2016 ()
Where
37 km (23 mi) west of Blackwell, OK · earthquakes near Blackwell
Oklahoma today
every earthquake in Oklahoma in the last 24 hours
Magnitude
M 2.8 (ml)
Depth
8.0 km below the surface
Felt
no reports yet
Nearest
Grant County, 10 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3556 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 61 km (38 mi) from the epicentre. In Blackwell, 37 km away, the estimate is intensity II (weak). 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: Caldwell 22 km, intensity III · Blackwell 37 km, intensity II · Anthony 45 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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 36.8469, -97.6990. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Grant County, OK 10 km (6 mi) SW earthquakes near Grant County
Sumner County, KS 47 km (29 mi) NNE earthquakes near Sumner County
Kay County, OK 50 km (31 mi) E earthquakes near Kay County
Harper County, KS 50 km (31 mi) NW earthquakes near Harper County
Garfield County, OK 53 km (33 mi) S earthquakes near Garfield County
Alfalfa County, OK 57 km (35 mi) WSW earthquakes near Alfalfa 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. 2.5 10 km W of Lamont, Oklahoma
  2. 1.5 11 km W of Caldwell, Kansas
  3. 3.0 6 km E of Renfrow, Oklahoma
  4. 2.5 6 km WSW of Bluff City, Kansas
  5. 2.2 8 km ENE of Bluff City, Kansas
  6. 1.6 Kansas
  7. 1.8 9 km W of Bluff City, Kansas
  8. 2.6 5 km S of Nash, Oklahoma
  9. 1.8 5 km ESE of Freeport, Kansas
  10. 1.9 3 km SSE of Danville, Kansas
  11. 1.5 7 km S of Anthony, Kansas
  12. 1.6 7 km S of Anthony, Kansas
  13. 2.0 8 km N of Manchester, Oklahoma
  14. 2.0 3 km NNW of Freeport, Kansas
  15. 2.1 4 km NE of Bluff City, Kansas

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.