Subsidence in urban areas: the “Ytzhak Rabin” park (via Panama, Roma) case history

Abstract

In Rome urban area, within the garden dedicated to Ytzhak Rabin (a portion of the Villa Ada park), occurrence of a few collapses has been observed for the first time in September 2012. In the surroundings, presence of underground cavities- mainly catacombs- is conversely well documented by previous studies. Local authorities were immediately informed of sinkholes formation, because collapses occurred very close to a playground located in a highly frequented sector of the garden. Propagation processes of the phenomena, periodically monitored since their first observation, significantly fastened after a period of heavy rainfalls on Rome area in January- February 2014. Thus, multidisciplinary geophysical investigations have been started in agreement with Civil Protection of Rome Municipality, who has taken preliminary safety measures (installation of fences and danger signals). Hitherto, 28 sinkholes have been identified, aligned along a WNW-ESE trending zone, testifying localized collapses of the roof of underground cavities, probably belonging to the palaeocristian catacomb systems dug nearby Via Salaria. Preliminary geophysical prospections have been performed in a small test area, in order to verify methods applicability and thus program a systematic survey of the whole garden. Drillings, and direct exploration of the accessible galleries, will complete the reconstruction of underground geometry and conservation state of vaults and pillars. Once completed the hazard assessment, the planning of urgent works is expected in order to restore the complete use of the garden.