Il telerilevamento è una tecnologia avanzata che utilizza sensori remoti per raccogliere informazioni sulla superficie terrestre senza la necessità di un contatto diretto.
Nell’ambito dello studio dei terremoti e del loro effetto sui monumenti, il telerilevamento si rivela uno strumento indispensabile.
Grazie all'uso di immagini satellitari, droni e laser scanner, è possibile monitorare lo stato di conservazione dei monumenti e rilevare danni strutturali con grande precisione, anche in zone difficilmente accessibili.
Uno dei principali vantaggi del telerilevamento è la sua capacità di coprire ampie aree geografiche in tempi relativamente brevi, permettendo così un’analisi rapida dei danni subito dopo un terremoto.
Le immagini ottenute possono essere comparate con dati preesistenti, consentendo agli esperti di valutare con esattezza l’entità dei danni. Questo è particolarmente importante per i monumenti storici, spesso situati in zone sismiche e di inestimabile valore culturale.
Il telerilevamento permette di individuare fessurazioni, inclinazioni e altri segni di stress strutturale che potrebbero compromettere la stabilità di queste opere.
Articoli su Riviste Scientifiche:
In this paper, the non-invasive system MASSIMO is presented for the monitoring and the seismic vulnerability mitigation of the cultural heritage. It integrates ground-based, airborne and spaceborne remote sensing tools with geophysical and in situ surveys to provide the multi-spatial (regional, urban and building scales) and multi-temporal (long-term, short-term, near-real-time and real-time scales) monitoring of test areas and buildings. The measurements are integrated through web-based GIS and 3D visual platforms to support decision-making stakeholders involved in urban planning and structural requalification. An application of this system is presented over the Calabria region for the town of Cosenza and a test historical complex.
DOI
Terrestrial laser scanning (TLS) and drone-based structure-from-motion (SfM) photogrammetry allowed the study of soil deformations due to blast-induced liquefaction during an experiment carried out on 4 June 2018. The research aimed at both evaluating the measurement quality and estimating the rammed aggregate piers (RAPs) effectiveness in mitigating the effects of soil liquefaction. These effects mainly consist of subsidence and deposits of ejected and extruded materials. The comparison between multitemporal 3D models provided surface variation maps and volume changes. In addition, classical topographical leveling allowed the measurement of subsurface vertical displacement along a specific cross section. The results pointed out a significant reduction, higher than 50% of soil deformation in areas improved by RAPs installation; moreover, the corresponding volume variations were no more than about 37% of those occurred in the not improved area. Finally, a critical comparison between remote sensing and leveling suggested that surface variation maps could underestimate the area lowering up to 15% in this kind of terrain
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Monitoring damaged buildings in an area where an earthquake has occurred requires the use of techniques which provide rapid and safe measurements even in emergency conditions. In particular, remote sensing techniques like terrestrial laser scanning (TLS) can satisfy these requirements, since they produce very dense point clouds in little time and also allow an accurate geometric modeling of observed buildings. Nevertheless, strong constraints on TLS data acquisition geometry, such as acquisition distance and incidence angles, typically characterize an area in seismic emergency conditions. In order to correctly interpret the data, it is necessary to estimate errors affecting TLS measurements in these critical conditions. A reliable estimation can be achieved by means of experiments and numerical simulations aimed at quantifying a realistic noise level, with emphasis on reduction of artifacts due to data acquisition, registration and modeling. This paper proposes a data analysis strategy in which TLS-based morphological maps computed as point-to-primitive differences are created. The method can be easily used for accurate surveying in emergency conditions. In order to demonstrate the proposed method in very diverse situations, it was applied to rapidly detect deformation traces in the San Giacomo Roncole Campanile (Modena), the Asinelli tower (Bologna) and the Cantalovo Church (Verona), three buildings damaged by the Mw 5.9 Emilia Romagna 2012 earthquake (Italy). 2013 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS) Published by Elsevier
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A seismic sequence that included a moment magnitude MW = 5.9 earthquake struck three regions of Northern Italy (Emilia Romagna, Veneto and Lombardy) in May–June 2012. The sequence caused significant damage to several historical buildings and in some cases caused complete structural collapse. Cracks appeared in the belfry and cusp of the 69 m high, ∼3◦ leaning bell tower of Ficarolo (Rovigo). A project aimed at studying the geometry of the tower, possible local seismic amplification and soil-structure interaction began in early 2013 before the earthquake. The data were provided by terrestrial laser scanning, low-cost operational modal analysis and geophysical measurements. The repetition of the surveys during and after the seismic sequence, which was augmented by thermal imaging measurements, allowed an evaluation of the changes caused by the earthquake. In addition to an evaluation of the damage, the data allowed the development of a method based on fast and relatively low-cost measurements that provide useful information for cultural heritage management purposes. The results highlighted that the surveys can be carried out during a seismic emergency and that preventive measures can be carried out under reasonable time and budget constraints in high seismic hazard areas.
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In this article, we present a new data collection that combines information about earthquake damage with seismic shaking. Starting from the Da.D.O. database, which provides information on the damage of individual buildings subjected to sequences of past earthquakes in Italy, we have generated ShakeMaps for all the events with magnitude greater than 5.0 that have contributed to these sequences. The sequences under examination are those of Irpinia 1980, Umbria Marche 1997, Pollino 1998, Molise 2002, L’Aquila 2009 and Emilia 2012. In this way, we were able to combine, for a total of the 117,695 buildings, the engineering parameters included in Da.D.O., but revised and reprocessed in this application, and the ground shaking data for six different variables (namely, intensity in MCS scale, PGA, PGV, SA at 0.3s, 1.0s and 3.0s). The potential applications of this data collection are innumerable: from recalibrating fragility curves to training machine learning models to quantifying earthquake damage. This data collection will be made available within Da.D.O., a platform of the Italian Department of Civil Protection, developed by EUCENTRE.
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The conservation of architectural heritage usually requires a multidisciplinary approach involving a variety of specialist expertise and techniques. Nevertheless, destructive techniques should be avoided, wherever possible, in order to preserve the integrity of the historical buildings, therefore the development of non-destructive and non-contact techniques is extremely important. In this framework, a methodology for combining the terrestrial laser scanning and the infrared thermal images is proposed, in order to obtain a reconnaissance of the conservation state of a historical building. The proposed case study is represented by St. Augustine Monumental Compound, located in the historical centre of the town of Cosenza (Calabria, South Italy). Adopting the proposed methodology, the paper illustrates the main results obtained for the building test overlaying and comparing the collected data with both techniques, in order to outline the capabilities both to detect the anomalies and to improve the knowledge on health state of the masonry building. The 3D model, also, allows to provide a reference model, laying the groundwork for implementation of a monitoring multisensor system based on the use of non-destructive techniques.
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Previous experiments highlighted the possible existence of a relation between repeatability of point clouds obtained from Structure-from-Motion photogrammetry (SfM) represented by the standard deviation (a), and the nominal ground sampling distance (GSD). In particular, the empirical relation 3a ~ 2.5 GSD was found. For this reason, in-situ tests aimed at studying this relation were carried out. Data from seven surveys carried out in 2018-2022 time span allowed the comparison between 20 pairs of almost contemporary point clouds, generated by means of relative bundle adjustment (BA) without ground control points (GCPs) and then relatively scaled and aligned. In this way, the relation 3a = aGSD was found, where a= 2.5 ± 0.4. This result also suggested the use of the reverse procedure, where the scale factor (SF) is estimated from the standard deviation of non-metric point clouds, sigma_nmw by using the relation SFa = aGSD/3sigma_nmu· Additional checks proved that SFa differs from SF by 3%. This error is not acceptable error for length, area or volume measurements, but the estimated SFa is more than adequate for a fast, rough registration of photogrammetric models aimed at searching patterns or precursors of incipient phenomena in impervious/inaccessible areas or in emergency conditions.
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The Garisenda Tower in Bologna, standing 48 meters high with a significant inclination (~4°), is under continuous observation due to alerts from its monitoring system. The tower’s structural health has been the focus of numerous studies aimed at its conservation. This article enhances the understanding of the tower’s deformation state through laser scanning measurements, employing a novel approach. Unlike previous analyses that focused on individual façades, this study evaluates deformation patterns and their evolution from 2010 to 2023, considering the entire structure. The proposed method selects the statistically most reliable height bands for point cloud alignment, ensuring optimal co‑registration into a common reference frame. Difference maps between multitemporal point clouds reveal overall displacements and deformations, suggesting torsion and bending effects along the entire structure. The south side of the tower appears to be the most affected, and the overall condition in 2023 seems worse than in 2012, possibly due to the Emilia‑Romagna earthquake. This new information could be valuable for planning and designing restoration interventions.
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