QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6ml

Earthquake near Blackwell, OK

No earthquake was likely felt in Blackwell in the 24 hours to 9:23 am CST (15:23 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 2.6 earthquake was recorded 17 km (10 mi) west-northwest of Blackwell, OK, at 4:37 pm CDT on 17 October 2020 (21:37 UTC), 7.0 km deep.

USGS: 7 km N of Nardin, Oklahoma

91 km (57 mi) S of Wichita, KS

4:37 pm CDT, Oct 17, 2020 · · 7.0 km deep · released about 280 lb of TNT

10 km30 km60 km120 km N Kay County 28 kmGrant County 32 kmSumner County 41 kmNoble County 57 kmGarfield County 63 kmHarper County 65 kmCowley County 68 kmAlfalfa County 79 kmSedgwick County 90 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
4:37 pm CDT on 17 October 2020 ()
Where
17 km (10 mi) west-northwest of Blackwell, OK · earthquakes near Blackwell
Oklahoma today
every earthquake in Oklahoma in the last 24 hours
Magnitude
M 2.6 (ml)
Depth
7.0 km below the surface
Felt
no reports yet
Nearest
Kay County, 28 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2143 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 53 km (33 mi) from the epicentre. In Blackwell, 17 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 17 km, intensity III · Caldwell 23 km, intensity III · Ponca City 37 km, intensity II · Wellington 44 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 280 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 55,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 39,000× the energy of this one
  3. Around the size people start to feel M 3.0 3.5× the energy of this one
  4. This earthquake M 2.6 about 280 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 4.4 on 2019-05-17 — about 440 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 36.8725, -97.4490. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Kay County, OK 28 km (17 mi) ESE earthquakes near Kay County
Grant County, OK 32 km (20 mi) WSW earthquakes near Grant County
Sumner County, KS 41 km (25 mi) N earthquakes near Sumner County
Noble County, OK 57 km (36 mi) SSE earthquakes near Noble County
Garfield County, OK 63 km (39 mi) SSW earthquakes near Garfield County
Harper County, KS 65 km (40 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. 1.6 6 km ENE of Hunter, Oklahoma
  2. 1.7 7 km N of Nardin, Oklahoma
  3. 2.7 6 km N of Nardin, Oklahoma
  4. 1.5 10 km W of Lamont, Oklahoma
  5. 2.2 6 km ENE of Jefferson, Oklahoma
  6. 1.7 9 km ESE of Jefferson, Oklahoma
  7. 1.5 2 km S of Renfrow, Oklahoma
  8. 2.1 9 km W of Lamont, Oklahoma
  9. 1.9 9 km W of Lamont, Oklahoma
  10. 1.5 9 km W of Lamont, Oklahoma
  11. 1.6 9 km W of Lamont, Oklahoma
  12. 2.4 9 km W of Lamont, Oklahoma
  13. 1.7 9 km W of Lamont, Oklahoma
  14. 2.6 7 km NE of Mayfield, Kansas
  15. 2.1 9 km NE of Mayfield, 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.