Oklahoma earthquakes

M4.1 earthquake 6 km WNW of Medford, Oklahoma

A magnitude 4.1 earthquake struck 6 km WNW of Medford, Oklahoma on Fri, Aug 14, 2015, 4:25 PM CDT (21:25 UTC), 0 km (0 mi) below the surface.

A larger quake followed: M4.4 12 km ENE of Nash, Oklahoma. This one was a foreshock.

Medford forecast More in Oklahoma

Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 4.1 (Mwr, regional moment), light
Magnitude from: USGS National Earthquake Information Center
Local time: Fri, Aug 14, 2015, 4:25 PM CDT
UTC: 2015-08-14 21:25:40 UTC
Depth: 0.1 km (0.1 mi), shallow
Epicenter: 36.831° N, 97.801° W
Region: Oklahoma
Felt reports: 152
Strongest shaking: IV, light shaking
PAGER alert: Green
Tsunami flag: No
Status: Reviewed by a seismologist

What happened

The USGS’s account of the effects of this earthquake.

Felt (IV) at Wakita; (III) at Edmond, Enid and Tulsa. Also felt at Alva, Blackwell, Braman, Broken Arrow, Jenks, Mannford, Medford, Newalla, Oklahoma City, Perry, Ponca City, Sand Springs, Stillwater, Tonkawa and Yukon. Felt (IV) at Caldwell; (III) at Arkansas City, Newton and Wichita; (II) at Derby, Kansas. Also felt at Andover, Atchison, Attica, Augusta, Belle Plaine, Bluff City, Canton, Cheney, Eureka, Hazelton, Hutchinson, Kechi, McConnell AFB, Pratt, Reading, Salina, Sedgwick and Whitewater. Felt at Carthage and Kansas City, Missouri.

From the USGS event page for us100032ei. U.S. Geological Survey text and figures are in the public domain.

Shaking

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

Strongest estimated: IV, light shaking
Map: Automatic

USGS ShakeMap: estimated shaking intensity around the epicenter — Estimated shaking intensity. Map: USGS ShakeMap.

Did you feel it?

152 people reported to the USGS what they felt; the strongest reported shaking was V, moderate shaking.

Estimated impact

The USGS PAGER system estimates deaths and economic losses from the shaking and the population and buildings exposed to it.

Alert level: Green: little or no damage or loss of life expected

Fault motion and ground failure

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Faulting: Strike-slip
Moment magnitude: 4.1 Mwr
Nodal plane 1: Strike 35°, dip 64°, rake -162°
Nodal plane 2: Strike 297°, dip 74°, rake -27°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 3.8 km horizontally, 3.9 km in depth
Magnitude uncertainty: ±0.05
Station coverage gap: 43°
Stations used: 0

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Nearby

Within 100 km, magnitude 1.5 and up: at least 200 in the 60 days after this one and at least 200 in the 30 days before it.

After

The first 60 of at least 200.

Before

Earthquakes today Oklahoma earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us100032ei. Read Sun, Oct 4, 2026, 11:54 PM UTC.