Robert Weight and Dr. John McBride, Geology Department
A major archeological excavation is ongoing for a Roman site near Mt. Vesuvius in the modern town of Pollena Trocchia, Italy. The excavation is being pursued as collaboration between BYU and the University of Naples. The excavation is being done in a present day urban setting therefore the excavators must be strategic in their methods and guided by whatever tools possible to avoid public disruption. A ground penetrating radar or GPR survey was completed which provided images of buried structures, collapsed buildings, and horizontal volcanic ash beds covering the site. These geophysical methods have assisted in a more timely and calculated excavation of the archeological site.
As the excavation effort at Pollena Trocchia continues pertinent insight will be gained from the archeological findings. The site is believed to have been a major farmstead with substantial building structures that survived the classic 79 A.D. eruption of Mt. Vesuvius that buried nearby Pompeii and Herculaneum. This will give archeologists a window into the civilization that survived and adjusted to life in the region of Mt. Vesuvius for several centuries and who braved several more eruptions until finally being buried by a fifth century eruption. There is little known about the fifth century society living there prior to this particular volcanic eruption.
In May 2007 GPR data was collected at the Pollena Trocchia site, in the region of Mt. Vesuvius, and the well-known archeological sites of Herculaneum and Pompeii. Data was processed and initial interpretations made on location. Data was brought back to Provo for further processing and interpretation. Recommendations about the location of the ash-covered structures were then given to the excavators. These recommendations will aid in the continued excavation of the site allowing archeologists to know the location of ancient building structures before they dig. Ground penetrating radar or GPR is a non-invasive technique that uses radio waves to penetrate several meters into the ground. Reflections or echoes of the waves are recorded by a computer, which then creates high-resolution images of the upper two meters of earth. The archeological application of GPR is that it produces images of boundaries between materials with different electrical properties. The viability of this method at this specific site was tested in June 2006, because of the methods electrical conductivity constraints, and was found to be viable.
In May 2007 two BYU Geology faculty members and two BYU Geology students, namely Dr. John McBride, Bill Keach, John Yaede, and myself, respectively, completed the survey. The survey areas had to be cleared and flattened before the grids could be set up. We were assisted by Greg Macfarlane, a BYU Civil Engineering student who created two appropriately dimensioned, string GPR grids in areas adjacent to the already excavated Roman walls, which were of particular interest to the excavators. The lines of both grids were spaced one foot apart.
The GPR surveys were collected over the course of several days as weather permitted. We used a jogging stroller type of GPR device, which contained both the transmitting and receiving antennas in a single box, and that could be rolled easily along the string grid lines. GPR data was collected continuously along each individual line of both surveys in both the x-axis and y-axis directions of the rectangular grids. Processing of GPR data was completed on site and the data was then analyzed using both two and three dimensional interpretation software packages. Initial interpretation of GPR data showed buried pits from a previous excavation effort and the extension of an exposed outer wall of the farmstead. More detailed interpretations were difficult to make while on location and presented a challenge that needed more processing, and time to solve. Dr. McBride, Bill Keach, and John Yaede continued this effort after returning to Provo. Their further analysis allowed them to pinpoint some buried features of archeological interest, including walls, and collapsed structures. Recommendations were made to the University of Naples and BYU excavating team, accordingly.
The GPR survey at Pollena Trocchia was very successful. This is evidenced by the successful presentation of the initial results at a conference in Salerno, Italy, in the fall 2007, and by the request of the Geoarcheology Congress of Salerno in Salerno, Italy, for a published article in their next published issue. The published article is initially proposed to have the following authors and title: MCBRIDE J.H., KEACH R. W. II, YAEDE J., WEIGHT R., MACFARLANE G., MACFARLANE R.T., DE SIMONE G.R., SCARPATI C., JOHNSON D.J.- Preliminary Results of a Ground-Penetrating Radar Study of a Roman Archaeological Site in Pollena Trocchia on the Northern Flank of Mt. Vesuvius.
This project allowed me to be exposed and mentored in the use, processing, and interpretation of a state-of-the-art geophysical method. This experience also gave me the opportunity to gain interdisciplinary and international experience as an undergraduate geology student. I was able to be involved as a geologist in original archeological research in Pollena Trocchia, Italy while working with students and/or faculty from the BYU Classics Department, BYU Geology Department, BYU Civil Engineering Department, Università degli Studi “Suor Orsola Benincasa” di Napoli, Italy, Università degli Studi di Napoli Federico II, Dipartimento di Scienze della Terra, Italy. This project has served to strengthen established collaborative ties between BYU’s Department of Geological Science and the University in Naples, Italy. It has allowed the aims of BYU to be fulfilled as students and professors alike set a standard of good science and friendly collaboration while working with Italian students and professors.