S.C. Geological Survey studies Lowcountry fault line
By South Carolina DNR
Published: August 11, 2009
The S.C. Geological Survey, in cooperation with the University of South Carolina’s Department of Earth and Ocean Sciences and Earth Science Research Institute, conducted a two-mile seismic reflectivity study along SC Highway 27 north of Pringletown in Berkeley County during the week of June 15.
This work compliments the mission of the S.C. Geological Survey, which is to provide reliable, unbiased scientific information to public and private decision-makers involved with land-use planning, environmental protection and economic development, as part of the S.C. Department of Natural Resources (DNR) Land, Water, and Conservation Division. Find out more at: http://www.dnr.sc.gov/geology/seismic.htm.
The seismic study has verified drilling results that showed evidence of faulting in the shallow subsurface. The presence of faulting was initially interpreted from regional geophysical data as marking the northern edge of the buried Jedburg basin, one of many Mesozoic basins buried under the Coastal Plain. Geologists at the Geological Survey now refer to the fault line as the Pringletown Fault. Understanding where faults are in the area is important because the area of maximum damage of the highly destructive 1886 Charleston earthquake is an elliptical area roughly 20 by 30 miles trending northeast between Charleston and Jedburg, including Summerville, and was roughly centered at Middleton Place.
During the study, researchers use a weight-drop or “thumper” to generate data. Mounted on a four-wheeler, an engine drives a piston that pounds a metal plate against the ground, and geophones receive the resulting seismic signals. The “thumper” repeatedly sends vibrations into the ground at predetermined locations along the established line of the survey. Data collection is labor intensive and requires the continual movement of the thumper, geophones, and wires that send, receive, and transmit the seismic signals to the control “dog house” on a truck. Data collection also requires accurate GPS locations of the geophone stations, and the closing of the roads to minimize the interference with the signals. After the data are processed, geophysicists develop a subsurface profile of the geology.
Part of the work also will be directed toward for the potential safe implementation of a technology called carbon sequestration, also known as carbon capture and storage. Based on an oilfield practice, this approach stores carbon dioxide before it is emitted into the atmosphere by safely storing it in geologic formations, soils and vegetation, or in other environmentally safe forms. Data also were collected to determine the possibility of natural gas exploration in the area.
South Carolina’s natural resources are essential for economic development and contribute nearly $30 billion and 230,000 jobs to the state’s economy. Find out why “Life’s Better Outdoors” at: http://www.dnr.sc.gov/green/index.html.