Seismic Swarm S20251118.1 Recorded South of Whites City, New Mexico

A seismic swarm designated S20251118.1 was detected 54 km south of Whites City, New Mexico, beginning at 08:54 on 17 November 2025 and concluding at 01:38 on 19 November 2025. Over 40 hours and 44 minutes, the sequence produced 28 earthquakes with magnitudes ranging from 1.5 to 3.4. Depths were concentrated between 5 and 7 km, consistent with shallow crustal activity in the Delaware Basin.

The largest event reached magnitude 3.4 at 20:36 on 17 November, followed within minutes by events of 2.3 and 2.9. Earlier activity on the same day included a magnitude 2.7 at 15:26 and a magnitude 2.5 at 15:20. Subsequent events on 18 November featured a magnitude 3.0 at 00:18 and multiple events between 1.5 and 2.1. The final recorded shock was magnitude 1.7 at 01:38 on 19 November. Most events clustered in the first 24 hours, with activity tapering thereafter.

This swarm marks the twelfth such sequence in 2025. Historical records since 2000 show 29 swarms in the region, with notable increases in frequency during recent years: one in 2022, nine in 2023, seven in 2024, and twelve in 2025. These clusters typically involve low-to-moderate magnitudes and shallow depths, reflecting the tectonic setting of southeastern New Mexico.

The location lies within the Delaware Basin, a major subdivision of the Permian Basin. The basin formed during the late Paleozoic era through subsidence and sedimentation, accumulating thick sequences of carbonates, evaporites, and clastic rocks. Regional tectonics are influenced by the far-field effects of the Rio Grande Rift to the west and subtle basement structures. Natural seismicity occurs along reactivated faults, while fluid migration through sedimentary layers can modulate event rates. Depths of 5–7 km align with the transition from sedimentary cover into crystalline basement rocks.

Swarm behavior in this setting often arises from fluid pressure changes along pre-existing fractures. The tight temporal clustering and similar depths observed in S20251118.1 are characteristic of such processes. Comparable patterns appear in earlier swarms documented in the same area, supporting the interpretation of episodic, low-magnitude release rather than a single large rupture.

Ongoing monitoring by regional seismic networks continues to track activity in the Permian Basin. The recent uptick in swarm frequency underscores the value of dense instrumentation for distinguishing natural from anthropogenic influences on local seismicity.

References
SeismoSight internal swarm catalog S20251118.1
USGS earthquake catalog (historical swarm statistics 2000–2025)
New Mexico Bureau of Geology and Mineral Resources – Delaware Basin tectonic summary