AMERICUS (Mar. 18, 2014)—Georgia Southwestern States University is participating in a large-scale seismic experiment, called the Suwanee Suture and GA Rift basin, or SUGAR, experiment.
The principal investigators of the SUGAR experiment are Donna J. Shillington, Ph.D., from Lamont Doherty Earth Observatory and Columbia University; Daniel Lizarralde, Ph.D., from Woods Hole Oceanographic Institution; and Steven Harder, Ph.D., from the University of Texas-El Paso. Additionally, technicians from Incorporated Research Institutions for Seismology (IRIS), graduate students from different institutions, and undergraduate Geology students from GSW are assisting with the experiment.
This project is sponsored by the National Science Foundation and is associated with a much larger experiment called Earth Scope which is now located in the Eastern U.S. The goal of this experiment is to gain a better understanding of tectonic movement and evolution, particularly in the eastern United States.
“Continents have collided and broken apart repeatedly over earth's history, but we still don't fully understand what makes this possible,” explained Shillington. “Some studies suggest two things that might help: magma and/or weak zones in the continent left behind from previous geologic events. Magma can heat up and weaken the continent. If there are weak zones in the continent left over from previous events, it might be easier to break the continent.”
“Georgia is an excellent place to test these ideas,” Shillington continues, “because there is an old rift zone that formed during the first phases of the opening of the Atlantic Ocean. This rift zone is near a major weak zone [, the South Georgia Rift Basin,] that formed during a previous continent collision and at the center of one of the biggest volcanic outpourings in earth's history.”
The South Georgia Rift Basin, which starts in the southern part of South Carolina and extends in a southwestern direction through Georgia and into Alabama, is one of the largest Triassic rift systems formed during the early breakup stages of Pangea. The Suwanee Suture runs through the South Georgia Rift Basin from east to west.
The SUGAR experiment will be using crustal-scale seismic refraction data. The experiment has been divided into two parts: a western profile, which GSW is assisting with, and an eastern profile that will be take place in 2015. These profiles, or lines, are roughly 170 miles long, and run north to south, crossing the South Georgia Rift Basin and the Suwannee suture. The western profile spans roughly from Columbus, Ga., to Valdosta, Ga., and intercepts Americus, where the field team is stationed. The eastern profile will span from Milledgeville, Ga., to around Waycross, Ga., with Vidalia, Ga., being the field station.
“Georgia Southwestern is participating in this project by providing some student volunteers and by acting as a logistical base for their operations,” said Sam Peavy, Ph.D., professor of Geology at GSW. “In particular, the students and scientists are operating out of the Florrie Chappell gym.”
Several GSW geology students will also be working on the experiment during Spring Break.
“These students will gain valuable experience as they participate in a major research project that is well beyond anything we could provide for them ordinarily,” added Peavy.
The experiment will provide information about the South Georgia Rift Basin by using sound waves.
“We are using sound waves to image geological features up to 40 km beneath the earth's surface along a 300-km-long transect across southwest Georgia,” said Shillington. “The sound waves will be generated by 12 controlled blasts in deep holes and recorded on over 1000 small seismographs [devices that read sound waves].”
The experiment began last week. Fourteen teams of two, including GSW students, deployed the seismometers along the profile in holes that have been recently drilled. The process took two to three days. The controlled blasts will soon be detonated. The detonations will occur during the night and are far away from any houses or structures. The detonations will only be detectable by those who are very close by.
Once the detonations take place, the seismographs will be retrieved and over the next couple of days, the data will downloaded.
For more information about SUGAR, please click here or contact Sam Peavy at (229) 931-2330. For more information on Earth Scope, see earthscope.org.
Caption--The seismographs are set in the earth in shallow holes roughly six inches deep.
Caption--Semir Sarajlic, a graduate student from Georgia State University, and Weifang Sun, a graduate student from Georgia Tech, deploy one of the thousand seismographs.
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