During the course of two campaigns, an integrated geophysical survey was completed in the urban area of the ancient city of Gabii. Beginning in 2007, the utility of magnetometry survey at the site was tested over a 6-hectare area within the hypothesized line of Gabii’s ancient walls. These initial tests produced good results and were encouraging enough to warrant a large-scale magnetometry survey of Gabii’s urban area, a project that was carried out during the course of the summer and autumn of 2008. The high-resolution magnetometry survey (25×50 cm) ultimately covered more than 40-ha of surface, an amount that reflects almost the entire surveyable area within the walled area of the ancient city.

In tandem with the magnetometry survey was a systematic core-sampling survey that was carried out in summer 2008. Employing both manual and mechanical coring machines, the team collected data from 52 points, allowing for the construction of stratigraphical profiles along two axes across the site. The results of the core sampling, and resultant profiles, revealed the presence of well-preserved stratified deposits on the site. With the combined geophysical results, a picture of the subsurface deposits at Gabii began to emerge and a complex urban network was revealed, including the presence of a road system and the remains of architecture within the site. The urban grid itself represents an important outcome of the survey, in that primary urban centers tend not to have regularized urban grids, owing to their mode of formation, yet the survey data clearly revealed that Gabii has such a grid system, composed of a main trunk road whose profile follows the topographical contours of the down-slope of the volcanic crater of Castiglione and off of which radiate side streets.