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Geophysics survey starts in the western lower town.

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This morning we started the first of two new initiatives for the 2012 field season. The first is an electrical resistivity survey in the western lower town. Back in 2002, we conducted a magnetic gradiometry survey in this area, measuring small fluctuations in the earth’s magnetic field caused by subsurface architecture. In the western lower town, I was able to map what looked to be a large nearly square compound, possibly with open courtyards surrounded by single rows of mudbrick rooms. The building seemed to be set against the city’s fortification wall at point where the wall zig-zagged as it turned from the southern edge to the western edge of the site.

We’ve speculated for years that this might be the location of an Assyrian military emplacement, or “fort” as they are sometimes called, paralled in other Assyrian cities. This year, we are conducting a new, more detailed, geophysical survey with two goals in mind. First, we want to see if we can confirm and add details to our geophysical map of the area. Second, we hope to identify a promising area for excavation in our final digging season at Ziyaret Tepe in 2013.

The survey data are being collected by a University of Akron anthropology major, Jordan Bell, who recently completed my Archaeogeophysical Survey course at the University of Akron, and Charlie Draper, a recent Cambridge University graduate. Charlie will be starting his M.Phil at Oxford University in the fall with a prestigious Ertegun Scholarship for the Humanities. This is the inaugural year for the Ertegun Scholarships, so it is quite an achievement for Charlie to win this competitive award.

Jordan (left), Mehmet (center), and Charlie (right) collecting the first resistivity data. You’ll recall from last year that our driver, Mehmet, plays an active role in the fieldwork and has lots of geophysical survey experience. We haul the water we need for the survey in the large plastic bottles and laboriously pour water from the small jug into each probe hole. Jordan is running the GeoScan RM-15 resistance meter.

The electrical resistivity survey, as you might recall from last year’s blog, creates a subsurface electrical field and measures the amount of resistance to the passage of an electrical current at points along a grid. In our case, mudbrick walls tend to retain moisture better than the surrounding soil, so they appear as linear low-resistance features. Our biggest challenge is in overcoming the problem that the topsoil has no moisture so we have to add water in order to overcome the problem of contact resistance. This means each probe hole must be predrilled, filled with water, and allowed to soak for a few minutes before we can use the mobile resistance meter shown in the picture. This process adds greatly to the efforts required to collect good data.

I’ll post the results as they are ready.

The second new initiative is the excavation of a possible Late Assyrian burial in Operation W. Excavation on this grave starts tomorrow morning. I’ll fill you in on the details in a subsequent post.

By matney

Dr. Matney is Professor of Archaeology in the Department of Anthropology and Classical Studies at the University of Akron. He is the Director of the Ziyaret Tepe Archaeological Expedition.

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