QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

Earthquake near Alva, OK

No earthquake was likely felt in Alva in the 24 hours to 12:57 pm CST (18:57 UTC). The last one was M 3.4, 144 km (90 mi) SSE, at 5:53 am CST on 7 November 2026, estimated intensity II (weak) in town; 23 felt reports to USGS. Every earthquake near Alva

This page: a magnitude 3.1 earthquake was recorded 24 km (15 mi) southeast of Alva, OK, at 5:06 am CDT on 27 July 2018 (10:06 UTC), 6.3 km deep.

USGS: 5 km SE of Dacoma, Oklahoma

5:06 am CDT, Jul 27, 2018 · · 6.3 km deep · released about 1,300 lb of TNT

Every earthquake near Alva Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alfalfa County 20 kmWoods County 33 kmMajor County 36 kmGrant County 67 kmBarber County 67 kmGarfield County 71 kmWoodward County 72 kmHarper County 73 kmBlaine County 84 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
5:06 am CDT on 27 July 2018 ()
Where
24 km (15 mi) southeast of Alva, OK · earthquakes near Alva
Oklahoma today
every earthquake in Oklahoma in the last 24 hours
Magnitude
M 3.1 (ml)
Depth
6.3 km below the surface
Felt
no reports yet
Nearest
Alfalfa County, 20 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2955 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 128 km (80 mi) from the epicentre. In Alva, 24 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: Cherokee 20 km, intensity III · Alva 24 km, intensity III · Helena 24 km, intensity III · Fairview 41 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× more

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 5.1 on 2016-02-13 — about 1,000 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 36.6324, -98.5139. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alfalfa County, OK 20 km (13 mi) ENE earthquakes near Alfalfa County
Woods County, OK 33 km (20 mi) WNW earthquakes near Woods County
Major County, OK 36 km (22 mi) S earthquakes near Major County
Grant County, OK 67 km (42 mi) ENE earthquakes near Grant County
Barber County, KS 67 km (42 mi) NNW earthquakes near Barber County
Garfield County, OK 71 km (44 mi) ESE earthquakes near Garfield County

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

Aftershocks so far

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

  1. 2.7 15 km SSE of Waynoka, Oklahoma
  2. 2.7 5 km WNW of Carmen, Oklahoma
  3. 3.2 15 km SSE of Waynoka, Oklahoma
  4. 2.7 17 km SE of Waynoka, Oklahoma
  5. 2.8 8 km SW of Waynoka, Oklahoma
  6. 2.7 3 km SE of Meno, Oklahoma
  7. 2.7 4 km NNE of Cherokee, Oklahoma
  8. 2.8 16 km SE of Waynoka, Oklahoma
  9. 2.7 8 km ENE of Nescatunga, Oklahoma
  10. 2.7 17 km SSE of Waynoka, Oklahoma
  11. 2.9 10 km WSW of Waynoka, Oklahoma
  12. 2.4 15 km SSE of Waynoka, Oklahoma
  13. 2.5 9 km SW of Waynoka, Oklahoma
  14. 2.5 5 km NW of Ames, Oklahoma
  15. 2.7 17 km SE of Waynoka, 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.