Earthquake · reviewed by a seismologist
M 1.6ml
Earthquake near Duncan, OK
No earthquake was likely felt in Duncan in the 24 hours to 2:27 pm CST (20:27 UTC). The last one was M 3.4, 123 km (77 mi) N, at 5:53 am CST on 7 November 2026, estimated intensity II (weak) in town; 23 felt reports to USGS. Every earthquake near Duncan
This page: a magnitude 1.6 earthquake was recorded 35 km (21 mi) northeast of Duncan, OK, at 6:34 am CDT on 17 April 2021 (11:34 UTC), 13 km deep.
USGS: 12 km SW of Erin Springs, Oklahoma
83 km (51 mi) SSW of Oklahoma City, OK
- When
- 6:34 am CDT on 17 April 2021 ()
- Where
- 35 km (21 mi) northeast of Duncan, OK · earthquakes near Duncan
- Oklahoma today
- every earthquake in Oklahoma in the last 24 hours
- Magnitude
- M 1.6 (ml)
- Depth
- 13 km below the surface
- Felt
- no reports yet
- Nearest
- Stephens County, 32 km SSW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2031 days ago
Earthquake alerts for Duncan, OK
Get a notification in this browser when USGS records an earthquake near Duncan, OK. No account or email needed.
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 minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth it was probably too small to be felt, even directly above it. In Duncan, 35 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.
Earthquakes near other towns within 30 km: Bray, Lindsay, Rush Springs, Marlow, Ninnekah, Maysville.
How big was it?
This earthquake released about 6.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,400,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
- Around the size people start to feel M 3.0 150× the energy of this one
- This earthquake M 1.6 about 6.4 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
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 34.7432, -97.7193. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Stephens County, OK | 32 km (20 mi) | SSW | earthquakes near Stephens County |
| Grady County, OK | 34 km (21 mi) | NNW | earthquakes near Grady County |
| Garvin County, OK | 37 km (23 mi) | E | earthquakes near Garvin County |
| McClain County, OK | 39 km (24 mi) | NE | earthquakes near McClain County |
| Cleveland County, OK | 63 km (39 mi) | NE | earthquakes near Cleveland County |
| Murray County, OK | 66 km (41 mi) | ESE | earthquakes near Murray County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
55 earthquakes have been recorded within 50 km since this one.
- 1.9 2 km SSW of Blanchard, Oklahoma
- 1.8 9 km E of Chickasha, Oklahoma
- 2.0 11 km SE of Ratliff City, Oklahoma
- 1.6 12 km SE of Ratliff City, Oklahoma
- 2.1 6 km NNW of Lindsay, Oklahoma
- 1.6 12 km SE of Ratliff City, Oklahoma
- 1.6 11 km SE of Katie, Oklahoma
- 2.1 10 km SE of Ratliff City, Oklahoma
- 1.5 2 km SSW of Blanchard, Oklahoma
- 1.7 2 km SSW of Blanchard, Oklahoma
- 1.8 2 km SSW of Blanchard, Oklahoma
- 1.8 7 km SW of Dibble, Oklahoma
- 3.3 7 km SW of Dibble, Oklahoma
- 1.6 7 km SW of Dibble, Oklahoma
- 2.0 9 km ESE of Chickasha, 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.