thA pair of moderate earthquakes that struck Wednesday night along the central coast were felt in parts of Silicon Valley and the East Bay, according to the U.S. Geological Survey. The largest of the two quakes, with a preliminary magnitude of 4.2, occurred at 10:26 p.m. on the San Andreas Fault at a depth of 4.1 miles, the USGS website reported. It was centered about 2 miles south of San Juan Bautista, about 50 miles south of downtown San Jose. More