Some people felt or heard the Summerville earthquake Saturday, but other town residents had no idea it occurred. It measured magnitude 2.6 on the Richter scale, said Pradeep Talwani, director of the South Carolina Seismic Network at the University of South Carolina.

The U.S. Geological Survey measured the quake at magnitude 2.4, said Joyce Bagwell, retired director of the Earthquake Education Center at Charleston Southern University.

"That's what we call a preliminary reading. You really need to get all your data in," Bagwell said.

Bagwell, who lives in Summerville, said she didn't feel the quake, but her son and grandchildren did. A quake has to be at least magnitude 2 to be felt, she said.

Pat Allan of Summerville said he felt and heard the quake. "It made a sonic boom, and it shook. It made more noise than it made shaking," he said.

Allan said Summerville quakes are not of particular concern to him. "I worry more about taxes," he said.

Marlena Myers, wife of Summerville Mayor Berlin Myers, said she didn't feel the quake, and neither did her husband. "That was news to me. I think that's a little scary," she said.

Kay Phillips, executive director of the Dorchester Children's Center, said she felt it at her home. "It was a pretty decent rumbling. It lasted for several seconds, enough for us to look at each other while it was going on," she said.

Cheri Tornabene was in a store in downtown Summerville when the quake happened at 3 p.m. "It sounded like someone fell in the room above us," she said. It wasn't much to Tornabene, who said she was in a major earthquake in Panama.

Summerville is the hot spot for earthquakes in South Carolina, but most of them are not felt.

The area was the epicenter of the great Charleston earthquake of 1886, the type of quake that occurs about every 500 years, Talwani said. The town sits on the "Woodstock fault," the fault line identified as the cause of the Charleston earthquake, he said.

The area experienced a magnitude 2.15 quake Feb. 22. Twelve small quakes struck in 2004; 22 in 2003.