Seismic Swarm S20230808.1: Analysis of Events Near Whites City, New Mexico

A seismic swarm designated S20230808.1 occurred 55 km south of Whites City, New Mexico, between 01:37 on 8 August 2023 and 01:32 on 10 August 2023. Over 47 hours and 55 minutes, the sequence included 36 earthquakes, with magnitudes ranging from 1.6 to 3.6 and focal depths primarily between 3 km and 8 km.

The swarm initiated with two magnitude-2.0 events at depths of 6 km and 5 km. Activity intensified on 8 August, featuring a magnitude-3.2 quake at 04:03 followed closely by additional events of 1.9 and 2.8. Peak magnitude reached 3.6 at 22:34 on the same day at 6 km depth. Subsequent events on 9 August remained moderate, with the largest at 2.8, while the sequence concluded with a magnitude-1.6 event at 6 km depth. Depths clustered around 5–6 km, indicating a shallow crustal source consistent with regional faulting patterns.

The location lies within the Delaware Basin, a major sub-basin of the Permian Basin in southeastern New Mexico and western Texas. This region features thick sedimentary sequences overlying Precambrian basement, with prominent fault systems including the Central Basin Platform boundary faults. Geological history records episodic tectonic activity since the Paleozoic, though modern seismicity is predominantly linked to anthropogenic factors such as wastewater injection from oil and gas operations.

Since 2000, five swarms have been documented in the immediate area, with one in 2022 and four in 2023. These clusters typically exhibit similar characteristics: short duration, low-to-moderate magnitudes, and shallow depths, distinguishing them from tectonic mainshock-aftershock sequences.

Such swarms provide insight into fluid-driven seismicity. The tight spatiotemporal clustering and lack of a dominant mainshock suggest pore-pressure diffusion along pre-existing fractures, a process amplified by industrial fluid disposal. Depths of 5–8 km align with the sedimentary-basement interface where injection effects are commonly observed.

Ongoing monitoring by regional networks continues to track activity in this tectonically quiet yet industrially active zone. Understanding these patterns supports improved hazard assessment for energy infrastructure and local communities.

References

USGS Earthquake Catalog
New Mexico Bureau of Geology and Mineral Resources reports on Permian Basin seismicity
SeismoSight internal swarm classification records