A series of three earthquakes shook the South Bay early Wednesday, according to the U.S. Geological Survey. The biggest of the three was a magnitude 4.3 shaker that happened at 6:16 a.m. about five miles east of Gilroy. Following that quake came shakers that were measured at a magnitude of 2.7 and 3.9, respectively. All three quakes happened within four minutes of each other and were centered within a five-mile radius of Gilroy, the USGS said.