A GEOPHYSICAL INVESTIGATION OF A KARST AREA NEAR LESLIE, GEORGIA

Resistivity and gravity measurements are being collected in Leslie, Georgia as part of a study to ascertain the risk of sinkhole collapse at the Dry Creek Farm. Sinkholes have been developing on the farm and in the surrounding area due to a four-year drought and local irrigation practices. A sinkhole on site was three feet in diameter when the study began in June, and is now greater than six feet in diameter. A new, three foot diameter sinkhole was found within 100 feet of a proposed building site in October.

Resistivity surveys have been conducted at the proposed building site using both the offset Wenner and expanding spread techniques in conjunction with a grid of gravity data. Similar geophysical surveys were conducted near the existing sinkholes on site for purposes of comparison. Preliminary analysis of the geophysical data from the proposed building site indicates that there are some variations in the subsurface that may be related to karst features. Additional analysis of the data will continue and include geophysical modeling of the data.