Analysis of Earthquake Swarm S20080502.2 Near Bodfish, California

The earthquake swarm S20080502.2 occurred 14 km south-southeast of Bodfish in Kern County, California. It began at 08:11 on 1 May 2008 and ended at 07:49 on 3 May 2008, lasting 47 hours and 37 minutes. A total of 42 earthquakes were recorded during this interval.

Events exhibited predominantly shallow focal depths between 0 and 5 km. Magnitudes ranged from 0.6 to 4.4, with the largest shock (magnitude 4.4) occurring at 08:11:43 on 1 May. Additional notable events reached magnitudes of 3.4 (twice) and 3.3. The sequence displayed typical swarm characteristics, featuring a rapid onset, multiple events of similar size without a dominant mainshock-aftershock pattern, and a quick decline in activity.

The Bodfish area lies within the southern Sierra Nevada foothills, where tectonic deformation arises from the broader interaction between the Pacific and North American plates. Local fault systems, including strands of the Kern Canyon Fault and proximity to the Garlock Fault, accommodate regional strain through distributed seismicity. This setting produces both isolated events and episodic swarms at shallow crustal levels.

Historical records indicate recurring swarm activity in the immediate vicinity. Since 1 January 2000, five swarms have been documented. Earlier episodes occurred in 2001 (one event), 2003 (three events), and 2004 (one event). These patterns suggest that the crust in this portion of Kern County periodically releases strain through clustered, low-to-moderate magnitude sequences rather than isolated large earthquakes.

The shallow depths observed in S20080502.2 are consistent with the regional geology, where brittle failure occurs within the upper few kilometers of the crust. Such activity underscores the ongoing seismic hazard in the southern Sierra Nevada transition zone.

References

SeismoSight internal swarm classification records.
USGS Earthquake Hazards Program regional tectonic summaries for Kern County, California.