Today marked our first day of training in Ground Penetrating Radar (GPR). I, along with seven others who will be at the survey in Shimron this summer, are spending a week in Johnson City Tennessee under the instruction of Dr. Eileen Ernenwein. Dr. Ernenwein teaches Geophysics and Geoarchaology at Eastern Tennessee State University.
GPR is only one of several Geophysical survey methods, and is perhaps the most complex. However, the advantage of GPR is that it can produce a 3D map of surveyed ground, unlike Magnetometry, for instance, which only provides 2D data.
GPR, as its name suggests, emits a radio wave into the ground, and records the reflection of the wave back to the antenna. As the wave encounters objects or changes in soil composition, which alters the velocity of the wave, part of the wave is reflected back towards the surface. By examining these reflections, it is possible to determine subsurface features.
Although GPR is mostly used for purposes other than Archaeology, such as construction, or Geological surveys, it can be very helpful for determining where on a site Archaeologists should dig most effectively. In our case, at Tel Shimron, we will be gathering data from the entire site, which is rarely done. It is a sizable undertaking!
Today, we spent the morning in lecture, learning just the very basics of GPR and how it works. After lunch, we headed out to Cane Notch (Pictured to the left), an excavation of a Cherokee site near ETSU. Although it was very cold, with little sun, and a chilling wind, excavations continue through the winter there. It was cold! It snowed for a while.
Our team set up two base lines, and several cross lines dividing the grid into 1 meter rows. We then took turns pulling the GPR device up and down the rows, gathering reflection data as we went.
Tomorrow we will begin by learning how to process this data, and will again finish the day in the field, collecting more data. I think the processing will be the most difficult part, but it is exciting to learn, and the team is great, I look forward to working with them this week, and in the summer!
GPR is only one of several Geophysical survey methods, and is perhaps the most complex. However, the advantage of GPR is that it can produce a 3D map of surveyed ground, unlike Magnetometry, for instance, which only provides 2D data.
GPR, as its name suggests, emits a radio wave into the ground, and records the reflection of the wave back to the antenna. As the wave encounters objects or changes in soil composition, which alters the velocity of the wave, part of the wave is reflected back towards the surface. By examining these reflections, it is possible to determine subsurface features.
Although GPR is mostly used for purposes other than Archaeology, such as construction, or Geological surveys, it can be very helpful for determining where on a site Archaeologists should dig most effectively. In our case, at Tel Shimron, we will be gathering data from the entire site, which is rarely done. It is a sizable undertaking!
Our team set up two base lines, and several cross lines dividing the grid into 1 meter rows. We then took turns pulling the GPR device up and down the rows, gathering reflection data as we went.
Tomorrow we will begin by learning how to process this data, and will again finish the day in the field, collecting more data. I think the processing will be the most difficult part, but it is exciting to learn, and the team is great, I look forward to working with them this week, and in the summer!
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