In this study, we present a framework for seagrass habitat mapping in shallow (5–50 m) and very shallow water (0–5 m) by combining acoustic, optical data and Object-based Image classification. The combination of satellite multispectral images-acquired from 2017 to 2019, together with Unmanned Aerial Vehicle (UAV) photomosaic maps, high-resolution multibeam bathymetry/backscatter and underwater photogrammetry data, provided insights on the short-term characterization and distribution of Posidonia oceanica (L.) Delile, 1813 meadows in the Calabrian Tyrrhenian Sea. We used a supervised Object-based Image Analysis (OBIA) processing and classification technique to create a high-resolution thematic distribution map of P. oceanica meadows from multibeam bathymetry, backscatter data, drone photogrammetry and multispectral images that can be used as a model for classification of marine and coastal areas. As a part of this work, within the SIC CARLIT project, a field application was carried out in a Site of Community Importance (SCI) on Cirella Island in Calabria (Italy); different multiscale mapping techniques have been performed and integrated: the optical and acoustic data were processed and classified by different OBIA algorithms, i.e., k-Nearest Neighbors’ algorithm (k-NN), Random Tree algorithm (RT) and Decision Tree algorithm (DT). These acoustic and optical data combinations were shown to be a reliable tool to obtain high-resolution thematic maps for the preliminary characterization of seagrass habitats. These thematic maps can be used for time-lapse comparisons aimed to quantify changes in seabed coverage, such as those caused by anthropogenic impacts (e.g., trawl fishing activities and boat anchoring) to assess the blue carbon sinks and might be useful for future seagrass habitats conservation strategies.

This work is focused on the assessment of the diagnostic potential of several geophysical methods when applied to the investigation of a rigid airport pavement. The potential and limit of each technique are evaluated as well as the added value deriving from their integration. Firstly, we reconstruct a high-resolution image of the pavement by a large electromagnetic and georadar screening. An advanced processing of georadar data, implemented through the picking of the arrival times of reflections for each profile, provides a quantitative estimation of the deviation between the design and the as-built thickness of layers. Additionally, electrical tomography has been applied to unequivocally identify the anomalous zones, where higher values of resistivity would be associated to porous zones that are prone to degradation and failure. The seismic tomographic survey had the additional purpose to recover the mechanical properties of the pavement in terms of both P- and S-waves and consequently of elastic constants (Poisson's ratio), whose values were consistent with those recovered in literature. The anomalies detected by each technique are consistent in their indications and they can be correlated to failure phenomena occurring at layer interfaces within the pavement structure or to unexpected variations of the layer thicknesses. The cost-effective geophysical campaign has validated the four-layered system deduced from the original design and has been used to reconstruct a high-resolution map of the pavement in order to discriminate fractures, crack-prone areas or areas where the as-built differs from the original design

In this work we present a non-invasive investigation of the Amphiteatrum Flavium, executed using the ground penetrating radar (GPR) technique, with the aim to improve the knowledge of the construction materials and techniques employed for building foundation. Therefore, the main goal of this work is to achieve quantitative and reliable information for assessing the seismic vulnerability of the structure. The GPR survey was performed through the Passage of Commodus, excavated within the foundation for a length of about 60 m. GPR data were acquired on the floor and on the lateral walls, using different antenna frequencies (80, 200, 600, 900 MHz) as they combine good resolution and depth of investigation. On the floor dataset, we detected three equally-spaced anomalies related to old utilities parallel to the passageway, whose roof is located at a depth of 1 m. In addition to this, the GPR radargrams clearly highlight horizontal layers within the foundation, related to the sequential development of works at the time of construction. GPR dataset acquired on the wall allowed us to detect the thickness of the concrete covering the foundation and to locate the extensions of the structural elements underground. Outside the foundation, the passage is built using bricks, with external walls about 1 m thick. Therefore, GPR dataset revealed that the foundation of the Colosseum is a heterogeneous multi-layer element, with the presence of cavity networks and buried elements related to the plinths of the load-bearing structures. This work confirmed that foundation was built over time by means of subdivisions into small sectors, probably both in the horizontal and vertical directions.