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Comparison of different approaches for landslide-induced damage assessment: the case study of Agnone (southern Italy)
No full textLandslides constitute one of the most important geo-hazards affecting southern Italy. Particularly, in this area slope movements have over time caused relevant socio-economic losses and, in some cases, also casualties. Prevention, prediction and monitoring of landslide phenomena play a keyrole to avoid or minimize their effects. In this work, damage suffered by facilities located within and surrounding a deep-seated landslide were classified through three different approaches. The investigated area is located in the municipality of Agnone (Molise region, central-south Italy), which is strongly affected by landslide processes. A main landslide event
that occurred in 2003 is still active, exhibiting slow and intermittent movements. In this contribution, three different approaches for landslideinduced damage assessment are compared and their discrepancy
discussed, highlighting the benefits and drawbacks of the different approaches. Finally, the future development of a new methodology and classification for infrastructures damage assessment is evaluated, merging
the procedures used in this work
Multi-band satellite radar data for landslide events management: an example from Central Italy
Full text linkOptimization of rainfall thresholds for landslide early warning through false alarm reduction and a multi-source validation
Full text linkIntegrating multiple information sources for landslide hazard assessment: the case of Italy
Full text linkAbstract Landslides are the most frequent and diffuse natural hazards in Italy causing the greatest number of fatalities and damage to urban areas. The integration of natural hazard information and social media data could improve warning systems to enhance the awareness of disaster managers and citizens about emergency events. The news about landslide events in newspapers or crowdsourcing platforms allows fast observation, surveying and classification. Currently, few studies have been produced on the combination of social media data and traditional sensors. This gap indicates that it is unclear how their integration can effectively provide emergency managers with appropriate knowledge. In this work, rainfall, human lives, and earmarked fund data sources were correlated to “landslide news”. Analysis was applied to obtain information about temporal (2010–2019) and spatial (regional and warning hydrological zone scale) distribution. The temporal distribution of the data shows a continuous increase from 2015 until 2019 for both landslide and rainfall events. The number of people involved and the amount of earmarked funds do not exhibit any clear trend. The spatial distribution displays good correlation between “landslide news”, traditional sensors (e.g., pluviometers) and possible effects in term of fatalities. In addition, the cost of soil protection, in monetary terms, indicates the effects of events
Spatial modeling of pyroclastic cover deposit thickness (depth to bedrock) in peri-volcanic areas of Campania (southern Italy)
Full text linkIn this study, the main focus is the application and improvement of four empirical models, which account for the pyroclastic cover deposit thickness (PCDT) spatial distribution with respect to the bedrock surrounding the Somma-Vesuvius volcano(Campania, southern Italy). Three models, which are already known in the literature, link the depth to bedrock to the morphologicalfeatures of a slope. An original model called SEPT (slope exponential pyroclastic thickness) is presented in this manuscript and combinesthe initial total thickness of ash-fall pyroclastic cover with the slope gradient. All models were applied and validated using field measurements derived from this and preceding studies in the study area. The main finding is that the spatial distribution of the depth to bedrock in mountainous peri-volcanic areas mainly depends on the initial thickness of air-fallen material at a given position and slope angle. These findings allowed for the recognition of an ash-fall pyroclastic depositional environment that is characterized by different processes from those existing in other geomorphological frameworks and in which the soil thickness along the slopes is controlled by the weathering of bedrock and the formation of soilin situ. Finally, in this research, a reliable approach is proposed that is also applicable to other peri-volcanic areas of the world to assess the spatial distribution of the depth to bedrock, which is a fundamentally important parameter in distributed geomorphologic and hydrologic modeling
Integration of field investigations and remote sensing techniques for the assessment of landslide activity and damage
Full text linkThe aim of the PhD thesis was to look for a relationship between the landslide-induced damage recorded on structures and facilities based on the results of several field campaigns and kinematic parameters quantitatively estimated by remote sensing techniques. Investigations were developed on two test sites: a deep-seated landslide in Colle Lapponi-Piano Ovetta in municipality of Agnone (Molise region, southern Italy) and the landslides affecting the southwestern sector of Volterra (Tuscany region, central Italy).
First of all, a re-enactment of the evolution of both landslides were conducted, by means of 3D reconstructions based on historical aerial series of images and the analysis of Persistent Scatterers of ERS1/2, ENVISAT and COSMO-SkyMed satellites. The 3D Points Clouds and models were developed on several sets of aerial historical images dating from different years starting from 1945 and 1954 for Agnone and Volterra, respectively. To better understand the morpho-evolutionary stages, a qualitative assessment of changes of volume were made combining the oldest and the latest 3D reconstructed Points Clouds. This interpretation, even if qualitative and not quantitative, can be helpful for understanding possible effects of future reactivations and as a support to realize mitigation plans, susceptibility maps and other useful for the local administrators. The Persistent Scatterers were used to monitor the evolution in recent years, up to 2015.
Then, for both case studies, the damage was revealed on structures and facilities by several field surveys and classified by means of five literature damage categorizations. During their application, some drawbacks and benefits of the methodologies were carried out and a new approach to improve the categorization of the damage on structures, facilities and ground surfaces was developed. This was conceived in two subsequent phases: i) a classification to use during the field campaign to quantify the severity of cracks and fractures on structures, facilities and ground surfaces; ii) an a posteriori ranking to apply on the entire structure, involving the extension of damage classes, performed by a cell-grid matrix. Furthermore, a damage recording scheme, useful for the recognition of cracks and fractures during the field surveys, was proposed. A critical comparison between the results obtained applying the different classification approaches, then followed. Buildings and facilities, for both sites, were categorized using also kinematic parameters such as velocity and maximum displacement measured along the Line Of Sight, derived by A-DInSAR, and their absolute values re-projected along the steepest local slope. Once characterized and categorized all structures and facilities of both sites of interest, a correlation between the surveyed damage classes and the deriving parameters by satellite were looked for. The investigation was carried to understand the behaviour of entire structures, subject to displacements. The first analysis was conducted on the Agnone test site where for several constructions an upper regression line between damage categories and velocity reprojected along the slope was recognized. Some outlayers were identified, mainly for low damage levels, then singularly investigated. To assess the reliability of all the structures, a matrix involving damage and velocity along the slope parameter acquired by ENVISAT and COSMO-SkyMed sensors was developed in order to obtain a classification. To validate the correlation and the reliability matrix the same procedure was applied to the Volterra site. Once asserted the validity of the relation between the velocity reprojected along the steepest slope and the classes of damage also for this area, the reliability matrix was applied on the constructions of the Volterra site. In this way, the relation between the displacement occurred during the period covered by ENVISAT and COSMO-SkyMed shows how the surveyed damage construction are related to the displacement. Some areas where damage occurred in the 2000 shows high reliability with ENVISAT recorded velocity, while others structures exhibits high reliability with COSMO-SkyMed data.
The results were interesting because they highlight the fact that for some construction there is correlation between velocity of displacement of the entire structure and affecting damage; for others, instead, the high damage is related to the differential settlement and not necessarily to a high rate of displacement velocity
From Picture to Movie: Twenty Years of Ground Deformation Recording Over Tuscany Region (Italy) With Satellite InSAR
Full text linkSynthetic Aperture Radar Interferometry (InSAR) techniques have been long exploited
for detecting and mapping slow-moving ground surface displacements due to their
millimeter accuracy, non-invasiveness and wide area coverage. A review on different
applications of Persistent Scatterers InSAR approaches, proposed and applied over
Tuscany region (Italy) across time, is here presented. The study area is characterized
by both subsidence of alluvial plains and landslides on hilly and mountainous reliefs.
Tuscany has a leading role in Italy in the field of interferometric applications: the first
InSAR analyses, which date back to 2003, were performed at local basin scale, by
exploiting various PSI-based approaches for risk mapping. The first InSAR applications
at regional scale date back to 2009, relying on historical SAR archives of ERS and
ENVISAT satellites for updating subsidence and landslide inventory maps at a certain
temporal date. Nowadays, the availability of Sentinel-1 SAR data with a regular and
systematic 6-days acquisitions plan, allows near-real time monitoring of deformative
scenario at regional scale rather than solely mapping of geo-hydrological phenomena.
Most recent innovative InSAR applications over Tuscany region scan the territory,
exploiting the regular repeat pass of Sentinel-1, and promptly highlight the sites affected
by the highest ground movements with high temporal frequency. Such approaches
permit us to pass from a static ‘picture’ of regional slope instability to a weekly
updated ‘movie’ with improved detail, useful for civil protection practices. These last
ongoing works significantly enhance the value of multi-temporal InSAR approaches for
investigating and managing geo-hazards over the Region
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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