ground penetrating radar the electromagnetic signal attenuation and maximum penetration depth

The use of high frequencies limits the penetration of the radar energy; this low penetration depends, at a parity of used frequencies, on the electromagnetic properties of the investigated material. The principal drawback is the elevated sensibility of the system to the variations of the EM properties of the environment immediately surrounds the antennas. The radar signals that arrive at the receiving antenna are attenuated and modified because of the selective absorption of the pulses by the ground, because of geometrical spreading, and because of an alteration of the actual amplitude due to the instrument amplification. In this paper, the absorption of the radar signal is taken into consideration and we determine, respectively, (i) the radar signal attenuation in the ground, (ii) the electrical conductivity (σ) and the relative dielectric permettivity (RDP) of the ground, and (iii) the maximum penetration depth of GPR in the ground

2D AND 3D seismic measurements to evaluate the collapse risk of cave in soft carbonate rock

The southern part of the Apulia region (the Salento peninsula) has been the site of at least fifteen collapse events due to sinkholes in the last twenty years. The majority of these occurred in "soft" carbonate rocks (calcarenites). Man–made and/or natural cavities are sometimes assets of historical and archaeological significance. This paper provides a methodology for the evaluation of sinkhole hazard in "soft" carbonate rocks, combining seismic and mine engineering methods.Acase study of a natural cavity which is called Grotta delle Veneri is illustrated. For this example the approach was: i) 2D and 3D seismic methods to study the physical-mechanical characteristics of the rock mass that constitutes the roof of the cave; and ii) scaled span empirical analysis in order to evaluate the instability of the crown pillar’s caves

METODOLOGÍAS INTEGRADAS PARA UNA NUEVA PROPUESTA RECONSTRUCTIVA DEL ANFITEATRO DE CATANIA

[EN] The roman amphitheatre of Catania stands in a very complex and interesting area where settlement dynamics and transformations have profoundly marked its urban landscape. Over the centuries, the urban and architectural histories together with the formation of the archaeological deposits have led to the complete obliteration of the monument and restricted knowledge of its plan and architectural development. Therefore, it constitutes an interesting context in which to experiment methods and techniques for architectural representation and the three-dimensional reconstruction of the monument[ES] El anfiteatro romano de Catania se encuentra en una zona compleja e interesante donde la dinámica de asentamiento y transformaciones han marcado profundamente su paisaje urbano. A través de los siglos, las historias urbanas y arquitectónicas, junto con la formación de los depósitos arqueológicos han dado lugar a la destrucción completa del monumento y el conocimiento de su plan de desarrollo arquitectónico. Por lo tanto, constituye un contexto interesante en el que experimentar métodos y técnicas para la representación de la arquitectura y la reconstrucción tridimensional del monumento.Malfitana, D.; Gabellone, F.; Leucci, G.; Cacciaguerra, G.; Ferrari, I.; Giuri, F.; De Giorgi, L.... (2016). INTEGRATED METHODOLOGIES FOR A NEW RECONSTRUCTIVE PROPOSAL OF THE AMPHITHEATRE OF CATANIA. En 8th International congress on archaeology, computer graphics, cultural heritage and innovation. Editorial Universitat Politècnica de València. 146-154. https://doi.org/10.4995/arqueologica8.2015.3555OCS14615

Towards an operative use of remote sensing for exploring the past using satellite data: The case study of Hierapolis (Turkey)

This paper is focused on the presentation and discussion of an object oriented approach, applied to the Hierapolis (Turkey) site, to automatically detect the subtle features linked to buried archaeological remains. The data processing is applied twice: (i) first, globally at the whole image and, (ii) second, at the significant subsets identified by global analysis, in order to refine the previously obtained categorization. Object oriented approaches are usually based on two main steps: i) first the segmentation, ii) then the classification. Herein, we first performed the unsupervised classification step and, then, the segmentation. This choice is given by the specificity of archaeological issue, in particular: (i) the subtle features/targets to be identified are partially or totally unknown and characterized by a very small spectral separability from the background, and therefore (ii) the discrimination between archaeological class and substrates likely suffers significant confusion. To cope with these issues, the first step is based on an unsupervised classification, which provides a first ‘rough’ categorization of pixels; the second step, based on the segmentation, enables us to extract the geometric shape, and, in turn, to only categorize as archaeological class those pixels belonging to geometrically (rectangular and linear) shaped clusters. Outputs from this classification identify rectangular and linear features of archaeological interest whose size suggested that they may be a farm and some sectors of an aqueduct, respectively. Results from satellite based analysis were successfully evaluated by georadar and geomagnetic prospection along with field survey. From georadar and geomagnetic prospection we were able i) to confirm the presence of buried remains and ii) to detail and characterize these archaeological features at the subsoil level as well as to define the local stratigraphy. From field surveywe dated the detected buried remains to a period spanning from Imperial Roman to early Byzantine historical times

Valutazione del grado di carsificazione di un\'area a nord ovest di Lecce mediante indagini integrate geologiche e geofisiche

ItIn un’area posta a NW di Lecce e ad W di Salice Salentino, sono state condotte indagini integrate geologiche e geofisiche finalizzate ad un riconoscimento di primo approccio dell’andamento del reticolo carsico sommerso. La scelta dell’area è scaturita da osservazioni di campagna che evidenziavano la presenza di più forme carsiche quali doline e vore, racchiuse in ristretti ambiti territoriali superficiali intensamente modificati dall’uomo e potenzialmente soggetti ad inquinamento oppure alla captazione di acqua dalla falda.EnIn an area located N-W of Lecce, near Salice Salentino, geological and geophysical integrated investigations have been conducted to determine the underground course of the karstic network, whose knowledge would be of fundamental importance both for its protection and for a rational exploitation of the territory. The choice of the area has been (in this sense) favoured by the presence of numerous karstic forms as dolines and sinkholes, and from the evidence of potential sources of pollution, as anthropic settlement, widely cultivated areas, particularly vineyards, as well as wells for water supply

The potential of integrated GPR survey and aerial photographic analysis of historic urban areas: A case study and digital reconstruction of a Late Roman villa in Durrës (Albania)

This paper focuses on the results of a joint geoarchaeological research project of urban historical remains in the ancient Roman city of Durrës, Albania. The project began with a desk-based analysis of all the historical and archival evidence including aerial photos from the 1920s–40s, a period before major urbanization of the area and prior to the capture of satellite imagery in the 1960s. These aerial photographs were re-processed and then combined with ground-penetrating radar (GPR) imagery and used to locate a Late Roman villa in the city. The integrated results produced a visual idea of what the villa looked like, when analysed in conjunction with the known archaeological and historical literature. During analysis, different levels of data reliability and resolution have been identified, which inform methodological choices when undertaking reconstructions of the villa. These methodological issues have generic resonance in the reconstruction of urban landscapes

Osservazioni geologiche e indagini geofisiche sul carsismo della costa neretina

ItLa piana costiera compresa tra S. Isidoro e Serra Cicora (Nardò, LE) è sede di un sistema carsico attivo ed è caratterizzata da morfologie carsiche, tra cui numerose doline di crollo ("spunnulate"), la cui coalescenza causa sprofondamenti di ragguardevole estensione e potrebbe portare alla formazione di insenature costiere. I fenomeni di dissoluzione chimica preparatori degli eventi di sprofondamento, assumono notevole rilevanza territoriale, dal momento che sono presenti anche in altri tratti delle piane costiere salentine. Di tali processi, oltre all’incidenza nell’evoluzione del paesaggio litorale e delle linee di costa, va considerata anche la pericolosità ambientale, avendo essi interessato nel recente passato infrastrutture viarie e abitative. Le indagini elettromagnetiche con georadar hanno messo in luce cavità ipogee non individuabili dalla superficie. In particolare, le indagini geofisiche hanno prodotto i risultati migliori in aree con minore presenza di materiale conduttivo (terre rosse, depositi palustri e acqua di falda salmastra), dove maggiore è lo spessore dell’areato e, pertanto, minore è l’assorbimento dell’energia elettromagnetica da parte del mezzo.EnThe coastal plain between S. Isidoro and Serra Cicora (Nardò - Lecce), formed by Cretaceous and Pleistocene carbonatic deposits, is seat of an active karstic system. It is characterized by various karstic morphologies, among which there are numerous collapse sinkholes, locally named "spunnulate", that sometimes reach notable extension because of the coalescence of many sinkholes. The accelerated chemical dissolution of the carbonatic deposits, at the origin of speleogenetic phenomena responsible for the collapse, assumes remarkable territorial importance, since the preparing conditions are present also in other parts of the salentine coastal plains. Besides the incidence in the evolution of the coastal landscape and coastlines, the environmental hazard posed by these processes must be considered, since in the recent past they interested various road and housing infrastructures. For a more exhaustive description of the karstic system Ground Penetrating Radar investigations can be very useful; in the specific case such investigations revealed karstic cavities which could not be detected on the base of surface evidences only. Particularly, the geophysical investigations gave the most meaningful results outside the marshy zones, where the presence of conductive material (terre rosse, marshy deposits and brackish water) is lesser, the aerated layer is thicker and, therefore, the electromagnetic energy absorption by the medium is lower and the signal-noise ratio is higher

Integrated geophysical and geomatics study at Xrobb l-Ghagin archaeological site : preliminary results

This study reports the results obtained by combining geophysical methods and geomatis techniques to study the Xrobb l-Ghagin archaeological site. We use unmanned aerial vehicle equipped with different sensors in order to reconstruct the 3D digital model of the area with the main goal of obtaining quantitative information. In particular, we used optical and Lidar sensors mounted on our drone and we perform also ground-based topographic survey in order to properly georeferenced the obtained 3D digital model. Geophysics data (e.g. ambient noise vibration, electrical resistivity tomography and ground penetrating radar) have been collected to study potential buried features present at the site. The 3D model and geophysical investigations helped in identifying potential buried archeological structures as well as the mapping of shallow geological features as fractures, faults and caves.peer-reviewe

GPR and passive seismic investigations in the church of Santa Maria delle Grazie at Campi Salentina (Lecce, Italy)

In the present contribution we propose the results of an integrated measurement campaign including ground penetrating radar and passive seismic data achieved in the church of Santa Maria delle Grazie at Campi Salentina, a town close to Lecce, in southern Italy. The passive seismic results corroborate the interpretation of the main (quite numerous at it will be shown) anomalies identified thanks to the GPR investigation.peer-reviewe