QuakeIndex

Earthquake · reviewed by a seismologist

M 2.0ml

Earthquake near Harper, KS

No earthquake was likely felt in Harper in the 24 hours to 6:30 am CST (12:30 UTC). The last one was M 3.4, 186 km (116 mi) S, at 5:53 am CST on 7 November 2026, estimated intensity II (weak) in town; 23 felt reports to USGS. Every earthquake near Harper

This page: a magnitude 2.0 earthquake was recorded 7 km (4 mi) southeast of Harper, KS, at 10:20 pm CDT on 21 August 2018 (03:20 UTC), 6.8 km deep.

USGS: 7 km SE of Harper, Kansas

73 km (46 mi) SW of Wichita, KS

10:20 pm CDT, Aug 21, 2018 · · 6.8 km deep · released about 31 lb of TNT

10 km30 km60 km120 km N Harper County 11 kmKingman County 38 kmSumner County 42 kmGrant County 53 kmBarber County 64 kmSedgwick County 65 kmAlfalfa County 66 kmReno County 79 kmPratt County 82 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
10:20 pm CDT on 21 August 2018 ()
Where
7 km (4 mi) southeast of Harper, KS · earthquakes near Harper
Magnitude
M 2.0 (ml)
Depth
6.8 km below the surface
Felt
no reports yet
Nearest
Harper County, 11 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3003 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 24 km (15 mi) from the epicentre. In Harper, 7 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: Anthony 12 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 31 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 480,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 340,000× the energy of this one
  3. Around the size people start to feel M 3.0 31× the energy of this one
  4. This earthquake M 2.0 about 31 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 4.0 on 2016-11-25 — about 970 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 37.2478, -97.9630. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Harper County, KS 11 km (7 mi) SW earthquakes near Harper County
Kingman County, KS 38 km (23 mi) NNW earthquakes near Kingman County
Sumner County, KS 42 km (26 mi) E earthquakes near Sumner County
Grant County, OK 53 km (33 mi) SSE earthquakes near Grant County
Barber County, KS 64 km (40 mi) W earthquakes near Barber County
Sedgwick County, KS 65 km (41 mi) NE earthquakes near Sedgwick County

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

Aftershocks so far

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

  1. 1.6 11 km N of Caldwell, Kansas
  2. 1.5 7 km S of Argonia, Kansas
  3. 1.9 7 km E of Freeport, Kansas
  4. 1.8 7 km S of Argonia, Kansas
  5. 1.7 7 km S of Argonia, Kansas
  6. 2.8 7 km S of Argonia, Kansas
  7. 3.7 7 km E of Freeport, Kansas
  8. 2.4 8 km NNE of Danville, Kansas
  9. 2.6 10 km N of Harper, Kansas
  10. 1.9 4 km E of Bluff City, Kansas
  11. 1.7 6 km ENE of Harper, Kansas
  12. 1.8 7 km NNE of Danville, Kansas
  13. 2.3 7 km NE of Danville, Kansas
  14. 2.1 6 km NE of Danville, Kansas
  15. 2.1 6 km NNE of Danville, 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.