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 4:52 pm CST (22:52 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 13 km (8 mi) northwest of Blackwell, OK, at 10:04 pm CDT on 31 May 2016 (03:04 UTC), 7.6 km deep. 1 person has reported feeling it to USGS.

USGS: 6 km SW of Braman, Oklahoma

89 km (55 mi) S of Wichita, KS

10:04 pm CDT, May 31, 2016 · · 7.6 km deep · released about 480 lb of TNT

10 km30 km60 km120 km N Kay County 23 kmGrant County 37 kmSumner County 40 kmNoble County 58 kmCowley County 62 kmGarfield County 67 kmHarper County 69 kmAlfalfa County 85 kmSedgwick 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
10:04 pm CDT on 31 May 2016 ()
Where
13 km (8 mi) northwest of Blackwell, OK · earthquakes near Blackwell
Oklahoma today
every earthquake in Oklahoma in the last 24 hours
Magnitude
M 2.8 (ml)
Depth
7.6 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Kay County, 23 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1562 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, 13 km away, the estimate is intensity III (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: Blackwell 13 km, intensity III · Caldwell 25 km, intensity III · Ponca City 34 km, intensity II · Wellington 42 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 36.8891, -97.3872. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Kay County, OK 23 km (14 mi) ESE earthquakes near Kay County
Grant County, OK 37 km (23 mi) WSW earthquakes near Grant County
Sumner County, KS 40 km (25 mi) NNW earthquakes near Sumner County
Noble County, OK 58 km (36 mi) SSE earthquakes near Noble County
Cowley County, KS 62 km (39 mi) NE earthquakes near Cowley County
Garfield County, OK 67 km (42 mi) SSW earthquakes near Garfield County

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

Aftershocks so far

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

  1. 2.7 8 km W of Deer Creek, Oklahoma
  2. 1.7 5 km ENE of Mayfield, Kansas
  3. 3.1 4 km ESE of Caldwell, Kansas
  4. 1.8 5 km ENE of Mayfield, Kansas
  5. 2.5 5 km WNW of Renfrow, Oklahoma
  6. 2.9 5 km WNW of Renfrow, Oklahoma
  7. 2.5 7 km ESE of Marland, Oklahoma
  8. 2.0 Kansas
  9. 3.0 4 km SSE of Braman, Oklahoma
  10. 2.7 5 km NNW of Red Rock, Oklahoma
  11. 1.6 10 km ESE of Bluff City, Kansas
  12. 2.7 10 km WNW of Caldwell, Kansas
  13. 1.9 7 km SSE of Argonia, Kansas
  14. 2.2 7 km SSE of Argonia, Kansas
  15. 2.0 7 km SSE of Argonia, 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.