What is the importance of the Kerkenes Dağ site?
There are two major ways in which it is important. First, there is an historical importance to the site as an enormous ancient city that was instrumental in the rise of Cyrus the Great, the first Persian emperor, and in the last presence of the Phrygian kingdom as well.
On a second level though, it’s a very unique archeological site that was basically built on a location where we don’t have any evidence that there had previously been a city laid out. It was planned, built and inhabited for about 40 to 60 years before it was destroyed and then not re-inhabited. So it’s almost in some ways like a Pompeii situation, only minus the volcano. You can get an idea as to the aspects of city planning that went into the site and then see how it was actually used for a brief period of time.
How was the city destroyed?
That we don’t exactly know. We presume it was either destroyed by Cyrus the Great, the first Persian emperor, or it was destroyed by Croesus, the king of Lydia. We have a story that was told to us by Herodotus that the two kings fought in the area of the city, and that Croesus had captured the city, but the he doesn’t mention who actually destroyed the city or under what circumstances. So there are a couple different scenarios that could have transpired. That’s something that we hope our project will allow us to discover.
You’ve been using some unmanned aircraft. How long have you been doing that?
We’ve been doing that since 2012 in terms of remote-controlled drones. However, even in 1993 and 1994 tethered ballons were used with cameras to take photographs of the site. We also used manned systems, such as a hot air balloon flight over the city and aerial photographs.
What systems are you using and how do they help you in your work?
We started with a Parrot drone in 2012, and then we moved onto DJI Phantoms 2s and 3s over the last couple of years.
There’s a couple different areas that are time consuming to do in archeology without the drones. One is planning in all the different remains and buildings and features that you find within a large excavation area. The unmanned vehicles are able to provide an overhead perspective in terms of photography. We can also bring the image in and, using a total station or GPS, we can rectify the photographs and digitize off that a stone-by-stone plan. We can then go back and check that plan in the field, and this process speeds up our planning work enormously.
The other thing we can do is incorporate some of the new photogrammetric techniques to generate 3-D point clouds from the overhead photographs and photographs we take on the ground. With that we can do fairly precise monitoring of standing architecture. We have a large gate, for instance, and we’re using photographs in this to try and monitor structural issues as they develop so that we can do mitigation work to stop the walls from falling over. So those are a couple different ways that using these drones can aid us enormously in our work.
What shortcomings are they having, and what would you like to see improved with them?
The big issues that we face is flight time and the difficulties of recharging batteries in the field. The site is actually a fair distance away from the excavation house. It’s on top of a mountain. And so we have to use lots and lots of batteries for extended flights. Ideally we would be able to have these fly much longer and be able to collect more data. This is also a problem for broader landscape survey applications. In trying to find archaeological remains across the landscape, the longer you’d be able to have the drones up and flying that the more area you could cover.
Another aspect that of a shortcoming would be the different types of sensing devices to mount under the drones. Less expensive near-infrared sensors or maybe something even like LiDAR would be extraordinarily useful.
What other sorts of technology have proven useful for your work?
We’ve used a lot of ground-based geophysical sensing devices, things like electrical resistance meters, magnetic gradiometers. We’ve also use GPS equipment since a couple years after GPS was first made available. We’ve used all of these technologies to help us map out large portions of the buried city without having to excavate everywhere.
More recently, we’ve gotten into 3-D scanners, but some of the work that we’re now doing with the photogrammetry is replace parts of that 3-D scanning work, in large part because of the time involved in terms of the collection of the data in the field.
Have you used unmanned aircraft before this excavation?
This excavation is where I first used them with the excavation. Our project has done a good job of identifying emerging technologies and testing them out. One wonderful thing is that with the datasets we’ve already collected, we can compare those result against for the results from new technologies as they emerge. With drones we were interested to see how they could be used to replace part of the recording system. We’ve also seen that it holds great promise for archaeological surveys as well. Surveys that I’ve done in the past would have greatly benefited from having this sort of technology.
How much longer do you think it will take to completely excavate it and understand the area?
To completely excavate the city would take an enormous amount of time. The Hittite capital of Hattusa, a similar sized site which is about 40 kilometers away in Turkey, has been excavated for well over 100 years. Major areas of the city have been excavated, but there’s still a lot they haven’t gotten to yet. With our city, we’re hoping to use these technologies to dig smarter and therefore to be able to answer questions without having to completely excavate everything. That also will allow future archeologists to come back and work at the site to answer new questions using new technologies or new methods. As for myself, I hope to be there for the next 25 or so years and then pass it on to other archeologists to continue the work.