Urban geomorphology of Cagliari city (Italy)

Cagliari is the main city of Sardinia and is located in the south cost of the island. It Is built on ten small rocky hills separated by valleys and bordered in the south by a wide sandy beach divide by a rocky cliff promontory. Both natural and man-made lagoons and ponds are widespread. Large areas of the city are affected by hydraulic, sinkhole, and landslide risks.

Geological and geomorphological field survey integrated by Uncrewed aerial vehicle, LiDAR and aerial photos remote sensing analysis were performed, in order to map and analyze the geomorphological hazard in a densely populated area and to define the Anthropocene of the study area.

Two lagoon barrier systems originated in the Last interglacial preserve the submerged shore lines of the Phoenician Punic period.

The hills on which the city is built are made up of Miocene marine carbonate deposits with cuestas morphologies. The edges are affected by landslide processes of sliding, rockfalls and toppling for the most part stabilized.

Since the Punic period, this area was affected by man-made changes to topographic surface and underground in particular mine works. The processes of stone material extraction for the construction of the city has created chasms and excavations that are currently key points for the genesis of the sinkholes

In the alluvial plain, flooding processes are widespread both in urban and extra-urban contexts due to the canalization of streams and subsidence processes.

The coastal and lagoon plain shows evidence of flooding processes and instability of the coastlines resulting from the relative sea level rise in relation to global climate change.

The results of a geomorphological study carried out in the urban area of Cagliari are summarized in a thematic map.