An earthquake of moderate strength rattled homes and businesses Friday along a 200-mile stretch from central to Southern California, possibly injuring two people, authorities said.

A man and woman were injured by an old avocado tree that fell on them shortly after the 4:06 p.m. earthquake, which measured 5.2 on the Richter scale. The quake was centered 11 miles northeast of Gorman, a sparsely populated area about 65 miles north of downtown Los Angeles.Authorities were not sure whether the quake was to blame for toppling the tree.

A section of the 400-mile-long California Aqueduct, which carries water from the central section of the state to Los Angeles, was shut down when electrical circuits at the Edmonston Pumping Station south of Bakersfield were damaged by the quake, said Mike McGregor, dispatcher for the state Department of Water Resources.