Revisiting Fara: Comparison of merged prospection results of diverse magnetometers with the earliest excavations in ancient Šuruppak from 120 years ago

Ancient Šuruppak, today Fara, was one of the major Sumerian cities in Mesopotamia. It was situated along one of the ancient watercourses of the Euphrates River. Findings date it back to the Jemdet Nasr period around 3000 bc with a continuous occupation until the end of the Ur III period around 2000 bc. Fara was first explored and excavated by the Deutsche Orient-Gesellschaft in the years 1902 and 1903 under the direction of Walter Andrae. Multiple excavation trenches with lengths up to 900 m transect the 1 km² wide mound and are still visible today which enables us to georeference the excavation maps. Today, the 2.2 km² wide archaeological area is dry and without any vegetation. Thousands of deep looting pits are covering the majority of mound which not only destroyed its upper metres but also challenge the application of geophysical prospection methods and their interpretation. The magnetometer prospecting of selected areas on and around the mound was carried out with three devices, two total field magnetometers and one gradiometer. The individual survey areas were combined in post-processing by applying a high-pass filter on the total field data sets and multiplying the vertical gradiometer data sets by a factor of two. This approach provides visually uniform magnetograms, despite being obtained by different devices, which simplifies subsequent visual interpretation. These magnetograms enable us to review, and to extend the results of the old excavations. The comparison show a good correlation in accuracy to the old drawings and positive identification of the already excavated features with magnetometry. Highlights of the survey are the discovery of the city wall confirming its existence, the layout of a unique building complex in the centre of the mound, likely a temple, traces of canals inside the city and an evaluation of magnetometer prospection over a looted area.