QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

Earthquake near Blackwell, OK

No earthquake was likely felt in Blackwell in the 24 hours to 7:02 am CST (13:02 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 2.5 earthquake was recorded 18 km (11 mi) north-northwest of Blackwell, OK, at 10:53 am CST on 31 January 2018 (16:53 UTC), 8.1 km deep. 1 person has reported feeling it to USGS.

USGS: 4 km NW of Braman, Oklahoma

82 km (51 mi) S of Wichita, KS

10:53 am CST, Jan 31, 2018 · · 8.1 km deep · released about 170 lb of TNT

10 km30 km60 km120 km N Kay County 25 kmSumner County 34 kmGrant County 42 kmCowley County 57 kmNoble County 64 kmHarper County 67 kmGarfield County 74 kmSedgwick County 82 kmAlfalfa County 89 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
10:53 am CST on 31 January 2018 ()
Where
18 km (11 mi) north-northwest of Blackwell, OK · earthquakes near Blackwell
Oklahoma today
every earthquake in Oklahoma in the last 24 hours
Magnitude
M 2.5 (ml)
Depth
8.1 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Kay County, 25 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3122 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 45 km (28 mi) from the epicentre. In Blackwell, 18 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 18 km, intensity III · Caldwell 23 km, intensity II · Wellington 35 km, intensity II · Ponca City 37 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.6× the energy of this one
  4. This earthquake M 2.5 about 170 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

The largest earthquake within 50 km since 2016 was M 4.3 on 2017-09-08 — about 500 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 36.9518, -97.3671. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Kay County, OK 25 km (16 mi) SE earthquakes near Kay County
Sumner County, KS 34 km (21 mi) NNW earthquakes near Sumner County
Grant County, OK 42 km (26 mi) WSW earthquakes near Grant County
Cowley County, KS 57 km (35 mi) NE earthquakes near Cowley County
Noble County, OK 64 km (40 mi) S earthquakes near Noble County
Harper County, KS 67 km (42 mi) WNW earthquakes near Harper County

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

Aftershocks so far

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

  1. 3.0 2 km NE of Renfrow, Oklahoma
  2. 3.6 3 km ENE of Renfrow, Oklahoma
  3. 2.9 3 km NE of Renfrow, Oklahoma
  4. 2.1 3 km NNE of Renfrow, Oklahoma
  5. 2.5 4 km NE of Renfrow, Oklahoma
  6. 1.7 7 km E of Caldwell, Kansas
  7. 1.7 6 km NW of Renfrow, Oklahoma
  8. 2.9 4 km WNW of Medford, Oklahoma
  9. 1.7 7 km S of Argonia, Kansas
  10. 2.5 Kansas
  11. 3.5 7 km E of Freeport, Kansas
  12. 2.7 1 km ENE of Bluff City, Kansas
  13. 1.6 7 km ESE of Freeport, Kansas
  14. 2.6 1 km SE of Renfrow, Oklahoma
  15. 2.6 7 km NNW of Lamont, 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.