At 9:51 p.m. on Aug. 31, 1886, the earth moved.
Outside of Charleston, S.C., near the epicenter of the earthquake, liquid sand boiled from the ground and the banks of the Ashley River slumped in.As the shock waves spread through the state, wells caved in, fires erupted from broken gas lines, railroads buckled, and a dam near Langley burst, sending a flood rolling across Aiken County.
Buildings were shaken to the ground in Charleston and damaged in every town within 200 miles. The initial wave was felt as far away as Chicago, and the aftershocks would continue for three years.
The 7.3 magnitude Charleston earthquake would go down in history as the most damaging ever in the eastern United States, killing 110 people and causing $5.5 million in damage in 1886 dollars or the equivalent of nearly $100 million today.
And although scientists predict that a quake of that magnitude will strike the East Coast only once every 1,100 to 1,300 years, no one knows for sure.
``Earthquake prediction is a popular subject for psychics and pseudo-scientists,' said William Smith, assistant director of the Earthquake Education Center at Charleston Southern University. ``But scientists have never been able to predict one. It could happen tomorrow.'
Schools and emergency management facilities across South Carolina will be observing Earthquake Awareness Week this week. A statewide drill will be conducted Wednesday beginning with a National Weather Service broadcast at 11:15 a.m.
Although major quakes are rare on the East Coast, South Carolina experiences smaller shake-ups on a regular basis, 16 or 17 a year on average. Of those, 75 percent occur within three seismically active areas in the Lowcountry.
But a major earthquake could be a trigger along the dozens of faults throughout the state, state geologist C.W. Clendenin said.
``Earthquakes don't just occur in the coastal plain,' he said. ``Earthquake awareness should be a statewide issue.'
Earthquakes are the result of plate tectonics shifts in the giant, floating masses of earth and rock that make up the continents. The most frequent earthquakes occur where the plates meet, such as along the San Andreas Fault in California.
In South Carolina, however, quakes are caused by shifts in smaller faults or bundles of faults within one of those plates, called intraplate earthquakes. The largest of these fault lines is the New Madrid Fault which runs roughly along the Mississippi River in the Midwest and mid-South.
Although intraplate quakes are more rare than quakes along the plates' edges, they can be equally or more powerful. An intraplate quake on the New Madrid Fault in the 1700s, for example, caused the Mississippi to reverse its course.
Determining what causes earthquakes here is difficult.
``We're still trying to figure out what makes this area tick,' Smith said. ``We don't know.'
Most of the state's earthquakes are very small, almost imperceptible minor quakes occurring deep in the earth.
However, every seven years or so a quake of 3 or 4 magnitude will shake the earth, rattling homes and jangling nerves.
Scientists are forecasting that a damaging earthquake (magnitude 6 or above) will likely strike the state within the next 30 years. And when it does, everything from highway bridges in the coastal lowlands to reservoirs in the Upstate could fall victim, said center Director Joyce Bagwell.
``Earthquakes don't get as much attention as hurricanes do,' she said. ``But they are one of the most damaging things that can occur in the state. If you value your family, you will take measures to protect yourself.'