Seismic Swarm S20230222.1: Analysis of February 2023 Activity Near Whites City, New Mexico

A seismic swarm designated S20230222.1 occurred in southeastern New Mexico, centered 54 km south of Whites City. The sequence began at 10:11 on 21 February 2023 and concluded at 10:53 on 27 February 2023, spanning 144 hours and 41 minutes. During this period, 68 earthquakes were recorded, with magnitudes ranging from 1.5 to 4.2 and focal depths primarily between 2 km and 9 km.

The swarm exhibited typical characteristics of clustered seismicity, featuring a rapid onset followed by numerous smaller events. The largest shock reached magnitude 4.2 at a depth of 6 km on 22 February at 07:44:10 UTC. Additional notable events included a magnitude 4.0 at 7 km depth later that day and several magnitude 3+ earthquakes clustered between 22 and 23 February. Activity gradually declined after 24 February, with the final recorded event of magnitude 2.5 at 6 km depth on 27 February.

This sequence aligns with patterns observed in prior swarms in the region since 2000, during which only three such episodes have been documented. The 2023 activity represents the second swarm recorded that year, following one in 2022.

The location lies within the Delaware Basin, a major subdivision of the Permian Basin in southeastern New Mexico and western Texas. The basin contains thick sequences of Paleozoic sedimentary rocks, including evaporites, carbonates, and clastics, overlying Precambrian basement. Regional tectonics involve a complex network of basement-involved faults that have been reactivated under varying stress regimes. The area experiences low to moderate natural seismicity, with historical events generally below magnitude 4.0 prior to increased monitoring.

Geological conditions in the Delaware Basin favor the occurrence of induced seismicity linked to fluid injection associated with oil and gas operations. Wastewater disposal into deep formations can elevate pore pressures along pre-existing faults, promoting slip. Depths of the recorded events are consistent with both shallow sedimentary layers and deeper basement structures commonly implicated in such activity.

The swarm provides insight into the temporal evolution of clustered events, with peak rates occurring within the first 48 hours and a subsequent decay following an Omori-like pattern. Most events remained below magnitude 3.0 after the initial energetic phase, indicating limited stress transfer to larger faults.

References

• USGS Earthquake Catalog (earthquake.usgs.gov)
• New Mexico Bureau of Geology and Mineral Resources, Permian Basin studies
• SeismoSight internal swarm classification data