Seismic Swarm S20240707.1 Recorded in Baja California

An earthquake swarm designated S20240707.1 occurred in Baja California, Mexico, beginning at 19:38 on 6 July 2024 and concluding at 01:03 on 16 July 2024. The events were located 93 km SSW of Alberto Oviedo Mota. Over 221 hours and 24 minutes, the swarm produced 101 earthquakes. Analysis of the first 100 events reveals magnitudes between 1.7 and 3.9, with the largest reaching 3.9 on 7 July at 00:47. Depths ranged primarily from 5 to 19 km, consistent with shallow crustal seismicity. Activity was most intense during the initial 48 hours, featuring repeated events above magnitude 3.0, followed by a gradual decline through mid-July. This swarm represents the third documented occurrence in the region since 2000. Prior episodes took place in 2010 and 2020, each limited to a single swarm event. Such episodic clustering underscores the intermittent nature of seismic release along local fault structures. The swarm area lies within the tectonically active Salton Trough, a pull-apart basin formed by the transition between the San Andreas transform system and the East Pacific Rise. The regional geology features northwest-striking strike-slip faults, including extensions of the Imperial and Cerro Prieto systems, alongside active geothermal fields. These conditions promote frequent small-to-moderate earthquakes and occasional swarms driven by fluid migration and aseismic slip.

References

SeismoSight internal swarm classification S20240707.1.
USGS Earthquake Hazards Program regional tectonic summaries for Baja California.
Servicio Sismológico Nacional (Mexico) historical seismicity records.