Scientists with the U.S. Geological Survey are using airborne technology to image and better understand the buried geology in the Charleston, South Carolina area. During the project, low-flying airplanes equipped with passive sensors will be used to create new 3-D images of Earth’s interior.

One of the USGS goals is to map deep faults in the region. Charleston was the site of a large earthquake in 1886, which did heavy damage to the city. Since then there have been only low levels of seismic activity, but scientists want to map and study the faults to assess how often such large earthquakes occur in the area. The region is considered to have elevated earthquake risk compared to other parts of the southeastern U.S.

Flights are scheduled to begin on Monday, May 20, 2019. The surveys will be flown over parts of Berkeley, Charleston, Clarendon, Colleton, Dorchester, Georgetown, Orangeburg, and Williamsburg counties in the southeastern part of the state. The USGS has contracted Terraquest Ltd. to fly the survey, and the planes and crew will be based out of the Santee-Cooper Regional Airport, South Carolina. Weather permitting, the surveys will take approximately 7-10 weeks to complete.

Many of these faults formed when the Atlantic Ocean first opened about 150-200 million years ago. 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. Those ancient lava flows produce subtle magnetic fields that can be detected with sensitive instruments.

“That ancient lava is one of the targets for the magnetic study, and our hope is to map any disruptions in that lava caused by faults,” said Anji Shah, USGS scientist in charge of the project. “We also want to learn more about the history of the opening of the Atlantic Ocean.”

Instruments on the airplane will measure variations in the Earth’s magnetic field created by different rock types up to several miles beneath the surface. The scientific instruments on the airplane are completely passive, with no emissions that pose a risk to humans, animals, or plant life.   back...