The earthquake that shook houses and rattled residents in the Summerville area shortly after 6:30 p.m. Wednesday was stronger than initially thought.

The U.S. Geological Survey initially reported the tremor at 2.4, then upgraded it to 2.5. By Wednesday night it was being reported as 3.0 on the Richter scale.

A 3.0 quake is definitely stronger than a 2.5 quake and will be noticed more, according to Erin Beutel, an earthquake expert at the College of Charleston. But even a 3.0 tremor is not strong enough to cause significant damage and is not all that unusual in the Summerville area, she said.

Three tremors at least 3.0 in scale have shaken Summerville since 2004, she said. The strongest one was recorded at 3.6 in 2008.

"This is normal active fault activity," she said.

Each year, 12 earthquakes with magnitudes between 1.1 and 3.0 typically shake up the Summerville area and is an indication that the faults that generated the 1886 earthquake continue to be active and capable of producing a large earthquake, Beutel said.

However, this level of activity is not a precursor to a larger event.

It's likely this tremor was noticed more because it hit around supper time when more people were at home, she said.

The quake was recorded at 6:38 p.m. and was centered a mile south southeast of Summerville, two miles west of Ladson and six miles west of Goose Creek, according to the U.S. Geological Survey.

The tremor sent tweets flying from Summerville, Goose Creek and North Charleston.

Many reported feeling a strong jolt, and some said they heard a loud boom.

"This one felt like somebody ran into the building," said Archie Thompson, a drug and alcohol counselor at the Dorchester County offices building on Main Street in Summerville.

Some said they ran out into the street after the jolt. That's a bad idea if a really strong earthquake hits here again, Beutel said.

She advises getting on the floor under a sturdy table and holding on during a powerful earthquake.

Running outside just increases the chances you will get hurt.

Reach Dave Munday at 937-5553.