VERSATIL TOOLS: DIGITAL SURVEY AND VIRTUAL REALITY FOR DOCUMENTATION, ANALYSIS AND FRUITION OF CULTURAL HERITAGE IN SEISMIC AREAS

Abstract. The paper deals with an interdisciplinary research activity aiming at developing a digital and integrated tool able to collect several data concerning the cultural heritage, and to manage and communicate them to a wide community. The small church of San Menna, located in the hamlet with same name in the municipality of Lucoli not so far from L'Aquila city, was the object of the research. The church has been chosen for its historical significance, its architectural peculiarity and for the valuable artworks that it preserves. Based on a photogrammetric model of the church, also used for the remote analysis of cultural asset (planimetric and evolutionary hypotheses, three-dimensional stratigraphic analysis, etc.) a virtual word usable in Virtual Reality (VR) has been developed. The VR setting allows the accessibility of a digital semantic model with information that can be activated with special interactive hotspots (images, texts and audio), which are able to provide an immersive and all-encompassing experience to the tourist. The potentialities of the same tool in the context of diagnosis and conservation process related to cultural heritage in seismic areas, such as those of the Abruzzi Apennines, have also been investigated through the integration of forms concerning the significant features of the artistic assets surveyed in the construction

Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy)

Abstract. Thus far, studies on climate change have focused mainly on the variability of the atmospheric and surface components of the hydrologic cycle, investigating the impact of this variability on the environment, especially with respect to the risks of desertification, droughts and floods. Conversely, the impacts of climate change on the recharge of aquifers and on the variability of groundwater flow have been less investigated, especially in Mediterranean karst areas whose water supply systems depend heavily upon groundwater exploitation. In this paper, long-term climatic variability and its influence on groundwater recharge were analysed by examining decadal patterns of precipitation, air temperature and spring discharges in the Campania region (southern Italy), coupled with the North Atlantic Oscillation (NAO). The time series of precipitation and air temperature were gathered over 90 yr, from 1921 to 2010, using 18 rain gauges and 9 air temperature stations with the most continuous functioning. The time series of the winter NAO index and of the discharges of 3 karst springs, selected from those feeding the major aqueducts systems, were collected for the same period. Regional normalised indexes of the precipitation, air temperature and karst spring discharges were calculated, and different methods were applied to analyse the related time series, including long-term trend analysis using smoothing numerical techniques, cross-correlation and Fourier analysis. The investigation of the normalised indexes highlighted the existence of long-term complex periodicities, from 2 to more than 30 yr, with differences in average values of up to approximately ±30% for precipitation and karst spring discharges, which were both strongly correlated with the winter NAO index. Although the effects of the North Atlantic Oscillation (NAO) had already been demonstrated in the long-term precipitation and streamflow patterns of different European countries and Mediterranean areas, the results of this study allow for the establishment of a link between a large-scale atmospheric cycle and the groundwater recharge of carbonate karst aquifers. Consequently, the winter NAO index could also be considered as a proxy to forecast the decadal variability of groundwater flow in Mediterranean karst areas

A GIS-Based Hydrogeological Approach to the Assessment of the Groundwater Circulation in the Ischia Volcanic Island (Italy)

Assessing the variations in space and time of groundwater circulation in volcanic islands is of paramount importance to the description of the hydro-geo-thermal system and implementation of hydrogeological, geochemical, and volcanic monitoring systems. In fact, the reliable reconstruction of the groundwater potentiometric surface in such composite volcanic aquifer systems can enable the identification of the most advantageous strategies for both the sustainable use of groundwater resources and the management of volcanic risk. Geographical Information System (GIS) platforms can support the integration and analysis of many spatial and temporal variables derived from monitoring of active volcanoes and the elaboration of spatially continuous data. However, open issues still affect the reliability and general applicability of common spatial interpolation methods in the case of groundwater potentiometric surfaces. This is related to the assessment of the main stratigraphic and volcano-tectonic features affecting the hydraulic head changes. With regard to the dynamically very active Ischia Island (Italy), this study illustrates a GIS-based hydrogeological approach to identify the most accurate interpolation method for mapping the potentiometric surface in complex hydrogeological terrains. The proposed approach has been applied to the existing dataset (1977–2003) stored by Istituto Nazionale di Geofisica e Vulcanologia. Based on a careful geological and hydrogeological survey, a total of 267 wells, from 5 to 250 m in depth, were processed. The data pre-processing involved four meteorological time-series data (1922–1997) and six long records of piezometric water levels (1930–1994). As a result, knowledge of the delineation of rather homogeneous stratigraphic and volcano-tectonic structures at the basin-scale has improved. Thus, new, more reliable potentiometric surfaces of the four main geothermal areas closest to the coast were produced during both dry and wet seasons. The reliability of the processed potentiometric surface was then validated by comparing the spatially continuous data with complementary field data. These findings point toward an optimal interpolation approach for representing the seasonal and areal distribution of main hydrogeological parameters in complex aquifer systems. Finally, insights into variations of hydrological behavior at an active volcanic area will foster an understanding of possible involvement of fresh and thermal waters in triggering phreatic explosions

Locking-free two-layer Timoshenko beam element with interlayer slip

A new locking-free strain-based finite element formulation for the numerical treatment of linear static analysis of two-layer planar composite beams with interlayer slip is proposed. In this formulation, the modified principle of virtual work is introduced as a basis for the finite element discretization. The linear kinematic equations are included into the principle by the procedure, similar to that of Lagrangian multipliers. A strain field vector remains the only unknown function to be interpolated in the finite element implementation of the principle. In contrast with some of the displacement-based and mixed finite element formulations of the composite beams with interlayer slip, the present formulation is completely locking-free. Hence, there are no shear and slip locking, poor convergence and stress oscillations in these finite elements. The generalization of the composite beam theory with the consideration of the Timoshenko beam theory for the individual component of a composite beam represents a substantial contribution in the field of analysis of non-slender composite beams with an interlayer slip. An extension of the present formulation to the non-linear material problems is straightforward. As only a few finite elements are needed to describe a composite beam with great precision, the new finite element formulations is perfectly suited for practical calculations. (c) 2007 Elsevier B.V. All rights reserved

A comparison of methods for assessing groundwater vulnerability in karst aquifers: the case study of Terminio Mt. aquifer (Southern Italy)

The assessment of groundwater vulnerability to pollution is becoming even more important all over the world due to the increase of impacts of human activities on groundwater resources and the related risks to the human health, economics, and the environment. Owing to the variability of methods known for estimating groundwater vulnerability, basically depending on hydrogeological parameters considered and the scale of analysis, the comparison of results of different methods appears straightforward for identifying the best approach in a given hydrogeological condition and reference scale. In such a view, this work attempts to assess the groundwater vulnerability of the Terminio Mt. karst aquifer, by applying four different groundwater vulnerability methods, index-based, and comparing results in order to identify the best performing one in karst environments. The study aquifer, located in the Picentini Mts Regional Park (Campania region, southern Italy) represents a strategic drinking water resource since Roman times and hosts massive groundwater resources which outflow mainly from tapped basal and subordinately perched springs. The peculiar characters of the study karst aquifer, which favour direct infiltration and groundwater recharge processes, as well as the occurrence of industrial, agricultural and grazing activities, make it very vulnerable to groundwater pollution, thus requiring a proper and careful territorial management. Beside the most frequently and generally used methods for assessing groundwater vulnerability, such as the DRASTIC and SINTACS, also DAC and COP methods specifically designed for karst aquifers were applied and mutually compared. Results of SINTACS, DRASTIC and DAC methods show groundwater vulnerability maps of the Terminio Mt. karst aquifer as chiefly characterized by two classes of intrinsic groundwater vulnerability, varying between the medium and high degrees. Furthermore, high and extremely high values of groundwater vulnerability were found in areas controlled by the shallow depth of the water-table. Instead, the COP method resulted as the most effective in identifying the endorheic areas and the related karst morphologies as very high groundwater vulnerability zones, therefore the most suitable in capturing specific hydrogeological features of karst areas that control groundwater pollution and vulnerability. Results obtained will support decision tools aimed at the land use planning and protection of karst aquifers from pollution in karst areas

Groundwater flow characterization and reconstruction of the hydrothermal system of Ischia as a tool for volcanic risk mitigation

The volcanic system of Ischia is characterized by an intense hydrothermal activity, documented since the early 16th century by the study of Iasolino [1588], which represents the first systematic analysis of the thermal springs of the island for therapeutic purposes. Later studies partially contributed to the enhancement of knowledge on the volcanic, hydrogeological and hydrothermal features of the island, highlighting the strong interaction between hydrothermal flowpaths and volcanotectonic processes. The reconstruction of the hydrothermal system becomes, therefore, a fundamental element for territorial planning, not only in terms of management of the huge water and geothermal resource, but also and above all in a perspective of prevention and mitigation of volcanic risk. Thermal springs, fumaroles and clay deposits due to the hydrothermal alteration of volcanic products testifies for the existence of an active deep hydrothermal system. However at Ischia the geochemical characterization of fluids and groundwater, performed through sampling and analysis of a discrete number of scattered springs, wells and fumaroles, has been used for the definition of the origin and structure of hydrothermal systems as a whole, as the hydrogeological information is incomplete. Moreover, volcanic hydrothermal systems, such as that characterizes the island of Ischia, are particularly difficult to analyze and outline, as the groundwater resources are the result of an articulated and dynamic interaction among meteoric water, sea water and fluids of deep origin. In such cases, the need for an interdisciplinary approach is evident, involving knowledge and research methods ranging from geology to volcanology, geophysics, geochemistry, mineralogy and hydrogeology. With particular reference to the functional and structural representation of the geothermal system of the island of Ischia and the resulting correlations with the volcanotectonic processes, the examination of previous information highlights the need to update and improve the knowledge on groundwater hydrodynamics and mineralization processes. Therefore, the present work represents a strong interdisciplinary action that, starting from the design and implementation of a database on the existing geological/volcanological and hydrogeological information, contributes to highlight the critical issues, define an operating scheme of the hydrogeothermal system of the island of Ischia, and upgrade its hydrogeological, geochemical and volcanic monitoring system, in order to contribute to the mitigation of volcanic and related risks. The knowledge of groundwater dynamics and pathways, in fact, is of fundamental importance for understanding the water/magma interaction processes in case of realimentation of the shallow magmatic system, and the assessment of the possibility of phreatic explosions occurrence. Moreover, the knowledge of the thermal fluids’ circulation and the related rock alteration processes is of paramount importance in the definition of the mechanic characteristics of rock masses and their proneness to failure

Groundwater flow process in the active volcanic system of Ischia Island (Italy)

The volcanic system of Ischia is characterized by an intense hydrothermal activity, documented since the early 16th century by the study of Iasolino (1588), which represents the first systematic analysis of the thermal springs of the island for therapeutic purposes. Later studies partially contributed to the enhancement of knowledge on the volcanic, hydrogeological and hydrothermal features of the island, highlighting the strong interaction between hydrothermal flowpaths and volcano- tectonic processes. The reconstruction of the interplay between hydrothermal and magmatic system becomes, therefore, a fundamental element for territorial planning, not only in terms of management of the huge water and geothermal resource, but also in a perspective of prevention and mitigation of volcanic risk. Thermal springs, fumaroles and mud deposits give beginning clues about deep hydrothermal conditions. Till now at Ischia, the local geochemical characterization of fluids and groundwater has been used for the definition of the origin and structure of the hydrothermal system as a whole, as the hydrogeological information is incomplete. However, volcanic hydrothermal systems, such as that characterizes the island of Ischia, are particularly difficult to analyze and outline, as the groundwater resources are the result of a complex and dynamic mixing among meteoric water, sea water and deep fluids. In such cases, the need for an interdisciplinary approach is evident, involving knowledge and research methods ranging from geology to volcanology, geophysics, geochemistry and hydrogeology. With particular reference to the functional and structural representation of the geothermal system of the Ischia island and the resulting correlations with the volcano-tectonic processes, the examination of previous information highlights the need to update and improve the knowledge on groundwater hydrodynamics and mineralization processes. Therefore, the present study aims at a strongly interdisciplinary action that, starting from the design and implementation of a database on the existing geological/volcanological and hydrogeological information, will contribute to highlight the critical issues, define an operating scheme of the hydro-geo-thermal system of the island of Ischia, and upgrade its hydrogeological, geochemical and volcanic monitoring system. The preliminary results improved the definition of the hydrogeological complexes and advanced knowledge of the groundwater flow conditions

Axial and Torsional Free Vibrations of Elastic Nano-Beams by Stress-Driven Two-Phase Elasticity

Size-dependent longitudinal and torsional vibrations of nano-beams are examined by two-phase mixture integral elasticity. A new and efficient elastodynamic model is conceived by convexly combining the local phase with strain- and stress-driven purely nonlocal phases. The proposed stress-driven nonlocal integral mixture leads to well-posed structural problems for any value of the scale parameter. Effectiveness of stress-driven mixture is illustrated by analyzing axial and torsional free vibrations of cantilever and doubly clamped nano-beams. The local/nonlocal integral mixture is conveniently replaced with an equivalent differential law equipped with higher-order constitutive boundary conditions. Exact solutions of fundamental natural frequencies associated with strain- and stress-driven mixtures are evaluated and compared with counterpart results obtained by strain gradient elasticity theory. The provided new numerical benchmarks can be effectively employed for modelling and design of Nano-Electro-Mechanical-Systems (NEMS)