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Abstract: As many other Italian towns, the historical center of Sassari was built using materials of prevailing local provenance. This is the reason why, following the program research of the Progetto Finalizzato “Beni Culturali”, the survey of materials constituting the buildings of the ancient city center of this town and of the decay typologies was carried out. All data were filed in a database and two thematic maps were also produced (materials/lithotypes, and weathering). On this basis and by means of a specific software, quantitative evaluations of lithotypes were obtained. The research evidenced that the use of different natural stones was conditioned by their availability and their different petro-physical features. Pedraforte (carbonatic conglomerate), showing better features but of limited availability, has been used for those portions of the buildings that needed better performances. Marly limestone and calcarenite are the most abundant materials. In particular, marly limestones, occurring in the immediate subsoil of the town, were widely used for plastered walls. Generally, all the surveyed materials display a poor state of conservation, except for those buildings recently restored. Almost all the weathering typologies have been recorded even though some of them are strictly correlated to a specific material. Pedraforte and ignimbrite are affected by alveolization whereas artificial patinae, erosion and granular disintegration have been mainly recorded for marly limestones and calcarenites. Oxalate patinae evidenced on Pedraforte in some buildings are possibly related to the use of organic matter for protective or even decorative purposes. A detailed study of the main façades of some relevant monuments contributed to a further understanding of the behavior of these materials whenever used as building stone and provided a useful tool for a correct restoration and conservation. The study also allowed to identify the exploitation areas of the main building materials used in the historical architecture of Sassari. Some of them are currently obliterated by recent building activity, and only few traces are still visible. This aspect evidences the importance of preserving the quarrying sites for their historical and cultural interest and, above all, for possible provisioning for restorations. [Copyright &y& Elsevier]

A detailed mineralogical and petro-physical characterization was carried out on Campanian Ignimbrite (CI) formation, a volcaniclastic rock widespread over the Campania region. This stone represented and still is an important building material since historical times. Given the huge extension of this formation (about 30 000 km2) the attention was mainly focused on the historical exploitation areas that provided building materials for the medieval village of Casertavecchia. Building stones (different facies of CI) used facciavista in some relevant monuments of this village were also characterized to carry out a comparison with the in situ corresponding rock. At the same time a complete survey of all the lithotypes used for the façades of the village as well as their state of conservation and weathering phenomena was also performed. As expected, CI in its different facies resulted the most common building stone, also affected by severe weathering such as lacks, alveolization and biological patinae, decay forms likely related to the high textural heterogeneity of the rock. Mineralogical and petro-physical characterization allowed to distinguish, within the investigated outcrop area, three different facies: dark, light and earthy grey tuff (DGT, LGT and EGT, respectively). Differences in mineralogical data mainly consist in the presence of clay minerals in the EGT facies only. K-feldspar always occurs in very high amounts (80–90%). As far as geomechanical parameters are concerned, the most pronounced differences are recorded in water absorption capacity, ultrasonic velocities and UCS values. These tests evidenced a substantial homogeneity of DGT and LGT facies and an overall worse behavior of EGT. Tests performed on CI samples from both monuments and outcrops gave similar results. This evidence strengthened the former hypothesis of a location of CI historical quarrying sites close to Casertavecchia. The only exception is the tuff used for the Mastio of the castle, whose chemical features are definitely referable to a different volcaniclastic formation. [Copyright &y& Elsevier]

• Historic center of Naples is one of the UNESCO word heritage sites. • Cathedrals, churches and chapels are subject to cavity collapse. • Places of worship are above a connected network of underground cavities. • DInSAR analysis suggest the presence of anomalous areas. • 95 places of worship of the historic center of Naples are susceptible to sinkholes. The historic center of Naples (southern Italy) is characterized by a variety of elements which, forming its cultural asset, have contributed to its recognition as a UNESCO World Heritage site. Among these, cathedrals, churches and chapels are particularly relevant due to their diffusion and differentiation in age. A singular feature of these places of worship is the presence of a frequently connected network of underground cavities. Such cavities, excavated for quarrying tuff blocks, are susceptible to sudden collapses generating sinkholes which in a number of cases have been responsible for the loss of human lives. On this basis and considering the importance of such elements as attractors of visitors, an analysis of susceptibility to sinkholes of cathedrals, churches and chapels has been here carried out. A sinkhole, cavities and places of worship inventory was prepared using available data and was used, in association to ongoing ground deformation data obtained by DInSAR. Results indicated that 40% of the inventoried sinkholes are a product of cavity collapses and in 45 cases cavities lie underneath places of worship. Geodetic data obtained by Differential Interferometric SAR technique indicate that approximately 1 km2 of the historic center of Naples is subject to ongoing subsiding deformation that in several cases is localized above cavities. The susceptibility map derived from available data indicate the presence of a zone where no cathedral, church and chapel can be subject to sinkholes (1) and 3 zones where they can be subject to sagging (2), potential future cavity collapses (3) and future cavity collapses anticipated by ongoing deformation (4); in detail, 34 places of worship are in zone 2, 57 in zone 3 and 9 in zone 4. Considering an increasing susceptibility level of the identified zones, the 9 places of worship located in zone 4 require a quick response in terms of characterization, stability analysis and real time monitoring have been identified. [ABSTRACT FROM AUTHOR]

Many of the UNESCO World Heritage Sites face geological threats which could have negative effects on the value, integrity and accessibility of their heritage assets. A relevant example is the Derwent Valley Mills UNESCO World Heritage site, one of the key sites of Britain's industrial revolution of the 18th century and located along the Derwent River Valley. Individual susceptibility scenarios of natural hazards in the area like collapsible deposits, compressible ground, debris flow, landslide, running sands, shrink-swell, soluble rock and flooding (both riverine and groundwater) are available, but a comprehensive product able to support disaster mitigation measurement and land planning still does not exist. On this basis, a multi-hazard susceptibility analysis was completed with the added benefit of reducing the complexity and providing a methodological framework for multi-hazard estimation. The analysis was completed in a GIS environment through an Analytical Hierarchy Process (AHP) multicriteria decision-making process. Since the AHP method is affected by a user selection bias, a quantitative Relative significance index was derived to rank the AHP factors during the susceptibility estimation. This index suggests that flooding is the principal natural hazard for the Derwent Valley Mills UNESCO World Heritage site. The multi-hazard susceptibility map also indicates that most of the areas where the mills are located are subject to significant susceptibility to natural hazards. [ABSTRACT FROM AUTHOR]