Earthquake · reviewed by a seismologist
M 3.3ml
Earthquake near Hennessey, OK
No earthquake was likely felt in Hennessey in the 24 hours to 9:09 pm CST (03:09 UTC). The last one was M 3.4, 57 km (35 mi) SSW, at 5:53 am CST on 7 November 2026, estimated intensity III (weak) in town; 23 felt reports to USGS. Every earthquake near Hennessey
This page: a magnitude 3.3 earthquake was recorded 12 km (7 mi) west of Hennessey, OK, at 9:37 pm CDT on 21 March 2021 (02:37 UTC), 6.0 km deep. 7 people have reported feeling it to USGS.
USGS: 11 km W of Hennessey, Oklahoma
86 km (53 mi) NNW of Oklahoma City, OK · 36 km (22 mi) SSW of Enid, OK
- When
- 9:37 pm CDT on 21 March 2021 ()
- Where
- 12 km (7 mi) west of Hennessey, OK · earthquakes near Hennessey
- Oklahoma today
- every earthquake in Oklahoma in the last 24 hours
- Magnitude
- M 3.3 (ml)
- Depth
- 6.0 km below the surface
- Felt
- 7 reports · strongest reported intensity V
- Measured shaking
- intensity IV (ShakeMap)
- Nearest
- Kingfisher County, 20 km SSE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1989 days ago
Earthquake alerts for Hennessey, OK
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 213 km (132 mi) from the epicentre. In Hennessey, 12 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: Hennessey 12 km, intensity III · Okeene 26 km, intensity III · Kingfisher 29 km, intensity III · Enid 34 km, intensity III · Crescent 43 km, intensity III · Okarche 43 km, intensity III · Fairview 44 km, intensity III · Watonga 46 km, intensity III. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 1.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 150,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 6,700× the energy of this one
- Magna, Utah 2020 M 5.7 4,700× the energy of this one
- This earthquake M 3.3 about 1.1 tons of TNT
- Around the size people start to feel M 3.0 this one released 2.4× 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 4.6 on 2018-04-09 — about 110 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 36.1133, -98.0290. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Kingfisher County, OK | 20 km (12 mi) | SSE | earthquakes near Kingfisher County |
| Garfield County, OK | 36 km (23 mi) | NE | earthquakes near Garfield County |
| Blaine County, OK | 45 km (28 mi) | SW | earthquakes near Blaine County |
| Major County, OK | 51 km (32 mi) | WNW | earthquakes near Major County |
| Logan County, OK | 57 km (35 mi) | ESE | earthquakes near Logan County |
| Canadian County, OK | 64 km (39 mi) | S | earthquakes near Canadian County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
50 earthquakes have been recorded within 50 km since this one.
- 1.9 6 km SSW of Lahoma, Oklahoma
- 2.0 5 km E of Hennessey, Oklahoma
- 1.5 7 km S of Meno, Oklahoma
- 1.8 3 km ESE of Fairview, Oklahoma
- 1.6 5 km E of Hennessey, Oklahoma
- 1.7 5 km WNW of Lucien, Oklahoma
- 2.0 3 km SE of Meno, Oklahoma
- 1.5 5 km N of Ames, Oklahoma
- 2.1 5 km N of Ames, Oklahoma
- 2.0 5 km N of Ames, Oklahoma
- 2.2 14 km SSW of Loyal, Oklahoma
- 1.5 6 km NW of Ames, Oklahoma
- 1.7 5 km N of Ames, Oklahoma
- 2.2 5 km N of Ames, Oklahoma
- 1.6 8 km ESE of Cleo Springs, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.