around the Coso Volcanic Field. The first large quake on July 4 registered M6.4 and the largest on July 5 registered M7.1. Within a week, more than 8000 (M1.0-4.5) smaller earthquakes had joined the swarm, though only 27 quakes larger than M4.5 occurred after the largest events. Surprisingly, there were no fatalities in California. Residents in Ridgecrest and neighboring unincorporated town Trona had moderate to severe property damage. Two structure fires, loss of power for up to 24 hours in some areas, and Trona was without water. Highway 178, one of the two ways in or out of Trona was blocked from rockslides and impassable shifted sections of asphalt. Ridgecrest had declared a state of emergency as a result. One fatality was reported in Nevada in the following days. Earthquake swarms are common in the Coso area, often producing hundreds of tremors over periods as short as a few days. This brisk and robust seismic activity is common in volcanic areas, such as Long Valley Caldera near Mammoth Lakes, and Yellowstone Caldera at Yellowstone. The Coso Volcanic Field shows examples of volcanic activity, probably last active 30,000 to 40,000 years ago, but ash emission and small cone building episodes may be Holocene (>10,000 years) in age. See also Coso Hot Springs Coso Range Coso Rock Art District Fossil Falls Lists of volcanoes References Further reading Eerkens, Jelmer W. and Jeffrey S. Rosenthal. 2004. Are Obsidian Subsources Meaningful Units of Analysis?: Temporal and Spatial Patterning of Subsources in the Coso Volcanic Field, Southeastern California. Journal of Archaeological Science 31:21–29. Elston, Robert G. and Charles D. Zeier. 1984. The Sugarloaf Obsidian Quarry. Report prepared for the Naval Weapons Center, China Lake, California, by Intermountain Research. NWC Administrative Publication 313. Ericson, Jonathon E. and Michael D. Glascock. 2004. Subsource Characterization: Obsidian Utilization of Subsources of the Coso Volcanic Field, Coso Junction, California, USA. Geoarchaeology 19:779–805. Garfinkel, Alan P. 2006. Paradigm Shifts, Rock Art Studies, and the "Coso Sheep Cult" of Eastern California. North American Archaeologist 27(3):203–244 Garfinkel, Alan P. 2007. Archaeology and Rock Art of the Eastern Sierra and Great Basin Frontier. Maturango Museum Publication Number 22. Maturango Press, Ridgecrest, California. Garfinkel, Alan P., Donald R. Austin, David Earle, and Harold Williams. 2009. Myth, Ritual and Rock Art: Coso Decorated Animal-Humans and the Animal Master. Rock Art Research 26(2):179–197. The Journal of the Australian Rock Art Research Association (AURA) and of the International