Southern California Earthquake Swarm
An earthquake swarm is being reported by the US GeologicService Earthquake Hazards Program in the Brawley SeismicZone immediately south of the Salton Sea in southernCalifornia. The swarm began on August 28, and reached asustained level of higher activity (quakes in the 4.5-5.0region of intensity) on August 31. The swarm is continuingat this time.
It is similar to swarms that occurred in the Brawley area inthe 1970s and 1980s. In the past, a quake on thecross-fault of the type that is taking place now triggeredmagnitude 6.2 and 6.6 events in 1987. The activity takingplace at present is ten miles from the major San Andreas,San Jacinto and Imperial faults, and shows no obvious signsof destabilizing them at this time.
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