Seismic Swarm S20240319.1: Analysis of Activity Near Prague, Oklahoma

Seismic swarm S20240319.1 occurred approximately 8 km northwest of Prague in central Oklahoma. The sequence initiated at 14:29 on 18 March 2024 and concluded at 14:25 on 28 April 2024, spanning 983 hours and 56 minutes. During this interval, 1,378 earthquakes were recorded. The swarm represents the third such event cluster documented in the region since 2000, following isolated swarms in 2011 and 2023.

Central Oklahoma lies within a zone of elevated seismic activity influenced by both natural tectonic features and anthropogenic factors. The area sits near the Nemaha Fault Zone and other basement structures that accommodate regional strain. Since the early 2000s, Oklahoma has experienced a marked increase in earthquake frequency, primarily attributed to wastewater injection associated with oil and gas production. Fluid injection can elevate pore pressure along pre-existing faults, promoting slip at depths typically between 2 and 8 km. Depths recorded during the present swarm (1–6 km) align with this pattern of shallow crustal seismicity.

Examination of the first 100 events reveals predominantly low-magnitude activity. Magnitudes ranged from –1.9 to 1.7, with the majority falling below zero. Depths clustered between 3 and 6 km, indicating consistent nucleation within the shallow basement. Temporal distribution showed an initial burst on 18 March followed by sustained but fluctuating rates through 20 March. The largest events in this subset reached magnitude 1.7 on 20 March at 08:49, occurring at 6 km depth. Negative magnitudes reflect sensitive network detection of microseismicity rather than felt shaking.

The 2011 Prague earthquake sequence, which included a magnitude 5.7 mainshock, remains the most significant historical benchmark for the area. That event and its aftershocks were linked to nearby injection wells. Subsequent regulatory measures, including injection-volume reductions, have altered swarm characteristics, yet episodic clusters continue. The 2023 and 2024 swarms fit within this ongoing pattern of induced or triggered activity.

Overall, swarm S20240319.1 exemplifies the low-magnitude, high-frequency sequences typical of Oklahoma’s induced-seismicity regime. Continued monitoring by regional networks remains essential for assessing evolving hazard potential.

References

USGS Earthquake Hazards Program – Oklahoma Seismicity
Oklahoma Geological Survey – Earthquake Catalog and Reports
Peer-reviewed literature on induced seismicity in the central United States (2010–2024)