Search

In the present paper, we present the main results of a diagnostic investigation on different paintings by Mattia Preti, belonging to the Cycle of the New Church of Sarria, located inside the Church of the Immaculate Conception of Sarria (Floriana) in Malta. The analysis was carried out on the occasion of the restoration process and, due to the short time available, only on some representative areas of each painting. A multi-technique approach was applied in situ, employing X-ray fluorescence spectroscopy (XRF) and Raman microscopy. The aim was to achieve information on the execution technique, in a completely non-invasive way, following the requirements of the restorers., peer-reviewed

In this contribution we will focus on some results achieved within the international bilateral project "Non-invasive investigations to enhance the knowledge and the enjoyment of cultural heritage" (funded by the Italian National Research Council and by the University of Malta). In particular, we will focus on some GPR and geoelectrical investigations performed on the so called Red Tower and on the so called White Tower, both on the western side of the island of Malta.

In this study, a multimethodological analysis involving optical and physical/chemical diagnostic techniques and 3D photogrammetric survey was successfully applied, for the first time, on the large oil on canvas St. Michael defeating Evil painting by Mattia Preti, located inside the Church of the Immaculate Conception of Sarria (Floriana) in Malta. Pigmenting agents, binder media, and raw materials were first characterized, both at elemental and molecular scales, through X-ray fluorescence spectroscopy (XRF), optical stereo microscopy (SM), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FT-IR), and gas chromatography coupled with mass spectrometry (GC-MS). The main goal was to properly identify the execution technique of this famous painter, the artist's palette, and possible nondocumented interventions. The 3D photogrammetric survey, on the other side, allowed us to noninvasively evaluate the extension of the areas that experienced restorations, and to properly map the domains of the different canvasses observed. The joints between canvasses suggested that the painting was folded and rolled up. In addition, the employment of a thermal camera gave evidence of the different consolidating material injection points used during the restoration to strengthen the painting. The obtained results offer useful information for the development of optimized restoration and conservation strategies to be applied and provide, at the same time, answers to open questions related to provenance and dating of the investigated artwork.

Within an E.U.-funded project, BESS (Pocket Beach Management and Remote Surveillance System), the notion of a geographic information system is an indispensable tool for managing the dynamics of georeferenced data and information for any form of territorial planning. This notion was further explored with the creation of a WebGIS portal that will allow local and regional stakeholders/authorities obtain an easy remote access tool to monitor the status of pocket beaches (PB) in the Maltese Archipelago and Sicily. In this paper, we provide a methodological approach for the implementation of a WebGIS necessary for very detailed dynamic mapping and visualization of geospatial coastal data, the description of the dataset necessary for the monitoring of coastal areas, especially the PBs, and a demonstration of a case study for the PBs of Sicily and Malta by using the methodology and the dataset used during the BESS project. Detailed steps involved in the creation of the WebGIS are presented. These include data preparation, data storage, and data publication and transformation into geo-services. With the help of different Open Geospatial Consortium protocols, the WebGIS displays different layers of information for 134 PBs including orthophotos, sedimentological/geomorphological beach characteristics, shoreline evolution, geometric and morphological parameters, shallow water bathymetry, and photographs of pocket beaches. The WebGIS allows not only for identifying, evaluating, and directing potential solutions to present and arising issues, but also enables public access and involvement. It reflects a platform for future local and regional coastal zone monitoring and management, by promoting public/private involvement in addressing coastal issues and providing local public administrations with an improved technology to monitor coastal changes and help better plan suitable interventions.

In recent years, we have been witnessing the widespread use of low-cost, increasingly high-performance Unmanned Aerial Vehicles, or UAVs, equipped with a large number of sensors capable of extracting detailed information on several scales and in an immediate manner. This study was motivated by the need to perform a geological survey in an area with difficult physical access, and to compare the results with those from conventional surveys. Here we used a Multirotor UAV equipped with a high definition RGB camera and the digital photogrammetry technique to reconstruct a three-dimensional model of the Selmun promontory, located in the northern part of the island of Malta (central Mediterranean Sea). In this area, the evident cliff retreat is linked to landslide processes involving the outcropping geological succession, characterized by the over position of stiff limestones on ductile clays. Such an instability process consists of a lateral spreading associated with toppling and fall of different-size rock blocks. Starting from the 3D model obtained from the UAV-photogrammetry, a digital geological-structural survey was performed in which we identified the spatial geometry of the fractures that characterize the area of the Selmun promontory by measuring strike, dip and dip direction of the fractures with semi-automatic digital tools. Furthermore, we were able to measure the size and volume of singularized rock masses as well as cracks, and their sizes were mapped in a GIS environment that contains a large number of digital structural measures. It is the first application of this type for the Maltese islands and the results obtained with this innovative digital methodology were then compared with those of the traditional field survey of the same area acquired during a previous campaign. This study demonstrated how the innovation of digital geological surveying lies in the possibility of mapping areas and geological features not detectable with traditional methods, mainly due to the high risk associated with the stability of the cliff or, more generally, the inaccessibility of some sites, therefore allowing the user to operate in safety and to detect in detail the most remote rocky outcrops.

In this contribution, we present some results achieved in the archaeological site of Le Cesine, close to Lecce, in southern Italy. The investigations have been performed in a site close to the Adriatic Sea, only slightly explored up to now, and where the presence of an ancient Roman harbour is alleged on the basis of remains visible above all under the current sea level. This measurement campaign has been performed in the framework of a short-term scientific mission (STSM) performed in the framework of the European Cost Action 17131 (acronym SAGA), and has been aimed to identify possible points where future localized excavation might and hopefully will be performed in the next few years. Both a traditional elaboration and an innovative data processing based on a linear inverse scattering model have been performed on the data., peer-reviewed

The Sicily dominates the central Mediterranean Sea. The Northern Sicily Continental Margin (NSCM) is a segment of the Appeninic-Tyrrhenian System whose upbuilding refers to both the postcollisional convergence between Africa and a very complex “European” crust (Bonardi et al., 2001) or AlKaPeKa (sensu Boullin, 1986) and the opening of the Tyrrhenian back-arc basin. Seismostratigraphic and structural analysis of a large number of available (from ViDePi project) and unpublished (from Department of Earth and Marine Science of the University of Palermo) multichannel seismic reflection profiles acquired across the NSCM, allow us to produce an accurate seismotectonic map, in order to obtain a useful tool for the assessment of the seismic hazard of the sea-land region. This first seismotectonic map has been realised from the overlapping of different geological layers that represent the main identified seafloor and sub-seafloor features, such as tectonic elements (normal and revers faults), earthquakes, heat flow, gravimetric (Bouguer) and magnetometric anomalies, Moho depth, masswasting, fluid escape structures (e.g. pockmarks, mounds, gas flares, and gas chimneys), sedimentary successions, and lateral and vertical motions. The NSCM is suitable to test this approach because it is located in a transitional area between the Sicilian-Maghrebian chain to the south and the Tyrrhenian back-arc basin to the north. Along this transect the Moho depth ranges from about 10 km, in the Marsili bathyal plain, to about 40 km, towards the northern Sicily coast. The Bouguer anomalies change from 180 mGal in the Tyrrhenian region to negative anomalies in central Sicily (-100 mGal), while positive magnetic anomalies characterize the volcanic edifices, both submerged and buried. While, the heat flow shows very high values across the southern Tyrrhenian Sea (200 mW/m-2) that decrease (30- 40 mW/m-2) towards the stable sector of the foreland area (Iblean plateau in SE Sicily). Along the NSCM, we distinguished, at a regional scale, different shallow and deep seismogenetic volumes. The eastern part of the Sicilian continental margin is characterised by a deeper seismicity related to the Ionian subduction, which is prevailingly linked both to extensional fault systems (Pollina, Messina strait) and to rightlateral NW-SE transcurrent systems (Vulcano- Lipari and Tindari-Giardini). While the western region shows shallow earthquakes (up to 25 km) of low to moderate magnitude (max Mw 5.9 on September 2002) occurring along an E-W trending belt and resulting from the brittle deformation of the Maghrebian chain. The focal mechanisms related to the main seismic shocks are in agreement with a dominant NW-SE compressive offset direction, with a right strike-slip component, and an antithetic NE-SW fault trend. Evidences of mass-wasting processes have been identified across the continental shelf and the continental slope and their spatial distribution, geometry, and seismic character suggest that the fluid seepage, oceanographic processes and the slope oversteepening could be important preconditioning factors, while the tectonic activity showing fault displacements during earthquakes is the main trigger. During the last 125 ky tectonic activity is evidenced by an uplift/subsidence patterns, decreasing from E to W. The continental regions are raised while offshore areas are subsiding, suggesting the occurrence of vertical differential movements. The GPS measurements document the active deformation with differential movements of individual blocks northwarddirected, in agreement with the shallow seismicity, as well as with the convergence between Sicily and Sardinia, with values of about 2-6 mm/y. The first step of this work produced the detailed seismotectonic map between the Castellammare and Palermo gulfs, including both the terrestrial and marine areas. Across the NSCM, we defined two main seismogenetic volumes that are produced by a NW-SE oriented compressional stress field defining an intraplate shallow seismogenetic zone. Though these results are only preliminary, we are developing a scientific product that can provide useful information in terms of seismic hazard in a complex region that includes both continental and marine sectors. Therefore, the identified geological features may be potentially geohazard elements for the neighbouring population and for the near goods, as well as submarine infrastructures (i.e. cables) and our seismotectonic map represent an important tool for monitoring the potentially seismogenic structures and assessing geohazards in marine and coastal environments.