M2.8 Earthquake 7 km NE of Lake Aluma, Oklahoma — September 20, 2020
2020-09-20 22:07:01 UTC (2020-09-20) · approx. 4:07 PM UTC-6 local
Felt by 71 people across nearby locations.
On September 20, 2020 at 22:07 UTC, a magnitude 2.8 shallow crustal earthquake struck 7 km NE of Lake Aluma, Oklahoma, at a depth of 6.8 km and coordinates 35.5892°, -97.3928°. This earthquake was detected by 97 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 153, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 2.8 releases seismic energy equivalent to roughly 223 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 50 m — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in Oklahoma, a region characterized by induced seismicity from high-volume wastewater injection into the Arbuckle Group formation, which reactivates ancient basement faults. View all earthquakes in Oklahoma.
Learn more: Magnitude scale · Aftershock sequences
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 71 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-97.3928°E
Technical Information
Common Questions
How strong was the magnitude 2.8 earthquake near Lake Aluma, Oklahoma?
The magnitude 2.8 earthquake that struck 7 km NE of Lake Aluma, Oklahoma on September 20, 2020 at 22:07 UTC had a depth of 6.8 km. For context, this was a minor earthquake typically detected only by instruments.
Where did the earthquake occur?
The earthquake epicenter was located at 35.5892°, -97.3928°, which is 7 km NE of Lake Aluma, Oklahoma. View all earthquakes in Oklahoma.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 2.8 earthquakes can continue for several days and gradually diminish over time.
Has Oklahoma had earthquakes this big before?
The largest recorded earthquake in Oklahoma was the M5.8 Pawnee earthquake of September 3, 2016. Today's magnitude 2.8 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: ok2020sofc). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, September 20, 2020). M2.8 Earthquake 7 km NE of Lake Aluma, Oklahoma — September 20, 2020. Retrieved November 28, 2020 from https://www.earthquaketracker.org/earthquakes/event/ok2020sofc/