How to prepare for an earthquake
When could an earthquake rock South Carolina? The U.S. Geological Survey wants to learn more about what’s buried in the earth’s past, and scanning below the state’s surface may provide clues.
Starting May 20, the federal agency will fly over Berkeley, Charleston, Clarendon, Colleton, Dorchester, Georgetown, Orangeburg and Williamsburg counties to map deep faults in the region, according to a news release.
Low-flying airplanes equipped with sensors will be used to create new 3-D images of the earth’s interior, USGS said in a statement. Scientist want study the region to assess how often large earthquakes might occur in the area.
In 1886, Charleston was shaken by an earthquake that heavily damaged the city. Since then, only low-level seismic activity has hit the region. Still, the territory from the Lowcountry and areas a bit farther inland are considered to have elevated earthquake risk compared to other parts of the Southeast, the U.S. Geological Survey said in a release. Subterranean fissures and ancient frozen lava flows exist underground.
Between 2017 and 2018, Pageland, a South Carolina town near the North Carolina border, was rocked by three quakes in six months. From September to November 2018, South Carolina was hit by string of minor quakes, including two in one day.
This year, only one seismic event tremored through South Carolina, according to the South Carolina Department of Natural Resources. A 2.5 magnitude quake centered in the Monticello Reservoir happened in January near Jenkinsville in western Fairfield County.
Many of the cracks in the earth’s crust formed when the Atlantic Ocean first opened about 150 to 200 million years ago, according to the Geological Survey.
“At that time there was also extensive volcanic activity that generated thick layers of lava now frozen and buried more than half a mile beneath the surface,” the agency’s statement said. “Those ancient lava flows produce subtle magnetic fields that can be detected with sensitive instruments.”
The ancient lava is one of the targets for the magnetic study, said Anji Shah, the Geological Survey scientist in charge of the project, in the news release.
“Our hope is to map any disruptions in that lava caused by faults,” Shah said in the news release. “We also want to learn more about the history of the opening of the Atlantic Ocean.”
Instruments on the plain will measure differences in the Earth’s magnetic filed produced by various rock types. The survey will go several miles beneath the ground.
“The scientific instruments on the airplane are completely passive, with no emissions that pose a risk to humans, animals, or plant life,” the agency said.
The project will take seven to 10 weeks, weather permitting.