New technologies to map hidden ancient Gerasa

Archaeology is evolving fast forward, thanks to the constant flow of new technology. One of the latest techniques in that field is using laser pulses from an aircraft to create an exact 3D map. This is called LiDAR or Light Detection and Ranging.

This revolutionary procedure is particularly useful to quickly map large areas with a high degree of accuracy. At present, Jerash, the ancient city of Gerasa (see: Alexander, founder of Gerasa), has been scrutinized. Until now, all we had to go by were old archival data and historical aerial photographs going back as far as the First World War. 

Results of the mapping process, showing newly identified features and previously mapped structures. The results demonstrate that a substantial number of archaeological features can be identified. These are complex to interpret, but the outline of a probable road network (Inset), and urban subdivisions are visible, along with a large number of subrectangular features likely indicative of building foundations.
[Picture from Proceedings of the National Academy of Sciences of the United States of America]

Urban development, here as elsewhere, has considerably changed the picture. Modern Jerash is a booming town and unfortunately for the archaeologists, at least 50% is built on top of old Gerasa.

Thanks to this new technology, researchers and archaeologists can see all those hidden remains, down to the most subtle and most difficult discernable features. Maps are lovely tools to study the past and looking at the 3D LiDAR map reveals so many details hitherto unknown. Much has been destroyed, but much is still there to be discovered and to be preserved for the future.

A good example is, for instance, the water management in ancient Gerasa that become apparent on the 3D maps (see: Water management in antiquity). A complex and sophisticated series of aqueducts and irrigation channels transported the essential water from nearby rivers and springs. 

I am convinced that there are many other clues about the organization and administration of ancient Gerasa waiting to be revealed. It will be wonderful to follow up on what is being exposed in Jerash and how this technology will be applied to other vestiges from antiquity.

The full article about this LiDAR technology is available in the Proceedings of the National Academy of Sciences of the United States of America, co-written by David Stott, Søren Much Kristiansen, Achim Lichtenberger and Rubina Raja.