QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

Earthquake near Alva, OK

No earthquake was likely felt in Alva in the 24 hours to 8:40 am CST (14:40 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 2.5 earthquake was recorded 8 km (5 mi) south of Alva, OK, at 6:04 am CDT on 16 August 2016 (11:04 UTC), 5.5 km deep.

USGS: 7 km S of Alva, Oklahoma

6:04 am CDT, Aug 16, 2016 · · 5.5 km deep · released about 170 lb of TNT

10 km30 km60 km120 km N Woods County 17 kmAlfalfa County 31 kmMajor County 48 kmBarber County 54 kmWoodward County 64 kmComanche County 71 kmHarper County 74 kmGrant County 79 kmGarfield 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
6:04 am CDT on 16 August 2016 ()
Where
8 km (5 mi) south of Alva, OK · earthquakes near Alva
Oklahoma today
every earthquake in Oklahoma in the last 24 hours
Magnitude
M 2.5 (ml)
Depth
5.5 km below the surface
Felt
no reports yet
Nearest
Woods County, 17 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3649 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 46 km (29 mi) from the epicentre. In Alva, 8 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: Alva 8 km, intensity III · Cherokee 28 km, intensity II · Helena 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 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 5.1 on 2016-02-13 — about 7,900 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 36.7355, -98.6727. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Woods County, OK 17 km (11 mi) W earthquakes near Woods County
Alfalfa County, OK 31 km (19 mi) E earthquakes near Alfalfa County
Major County, OK 48 km (30 mi) SSE earthquakes near Major County
Barber County, KS 54 km (34 mi) N earthquakes near Barber County
Woodward County, OK 64 km (40 mi) WSW earthquakes near Woodward County
Comanche County, KS 71 km (44 mi) NW earthquakes near Comanche County

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

Aftershocks so far

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

  1. 3.3 4 km NNE of Cherokee, Oklahoma
  2. 2.9 12 km SSE of Waynoka, Oklahoma
  3. 3.0 17 km SSE of Waynoka, Oklahoma
  4. 2.7 6 km NNW of Quinlan, Oklahoma
  5. 2.6 3 km ESE of Byron, Oklahoma
  6. 3.0 5 km NNW of Quinlan, Oklahoma
  7. 2.6 6 km NNW of Quinlan, Oklahoma
  8. 2.6 5 km NNW of Quinlan, Oklahoma
  9. 3.3 17 km SE of Waynoka, Oklahoma
  10. 2.8 17 km SSE of Waynoka, Oklahoma
  11. 2.7 17 km SSE of Waynoka, Oklahoma
  12. 2.6 17 km SSE of Waynoka, Oklahoma
  13. 3.2 17 km SSE of Waynoka, Oklahoma
  14. 3.3 17 km SSE of Waynoka, Oklahoma
  15. 2.6 5 km N of Quinlan, 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.