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Mountain landslides: Monitoring, modeling, and mitigation
Full text linkThis editorial paper summarizes the contents of the papers included in the Special Issue "Mountain Landslides: Monitoring, Modeling, and Mitigation". The Special Issue provides an overview of methodological papers, as well as some innovative research carried out in the field and in the lab. Even if most papers adopted an integrated approach, sections representing the three research issues outlined in the title can be drawn: the first deals with monitoring, the second focuses on modeling, and the third is related to mitigation. Regardless of the section, the papers included in this special issue put forward methodological and practical implications that, more than likely, can stimulate further research efforts and support the stakeholders to gain better knowledge of landslide hazards in mountain environments, with an aim to tackle the urgent issue of sustainable development in times of global change that can affect landslide occurrences in mountain chains of the world
Hillslope Processes and Climate Change
No full textThis chapter focuses on the relationships between hillslope processes and climate change, with special attention to the role of climate changes on the temporal and spatial occurrence of mass movements
ONE OF THE HAZARDOUS NEIGHBOURS OF THE VAJONT LANDSLIDE: THE HISTORICAL M. SALTA ROCK-BLOCK SLIDE-ROCK FALL
Full text linkIn the Vajont Valley (north-eastern Alps), the everlasting interactions between endogenic (tectonic, seismic, isostatic) and exogenic (glacial, slope, anthropogenic) processes have resulted in a hazardous environment. The most striking geomorpho-logical feature of the valley is the evidence of several landslide processes of different type, age, and size. The October 1963 catastrophic landslide is undoubtedly the most notorious one. However, the Pineda and Salta landslide events have left enduring signatures in the landscape of the valley. In particular, the wide landslide deposit upslope Casso, on the southern slope of M. Salta, derives from multiple overlapping events. Rock planar slides, topples, and rock falls occur since centuries, displaying a complex-composite style of activity. Nowadays, in this area, slope processes are still active and are threatening the village of Casso and the visitors of the 1963 disaster site
The influence of Holocene climatic changes on landslide occurrence in Europe
No full textThe paper deals at first with the problems and the sources of uncertainty to be considered while setting up an outline of the temporal occurrence of landslides with respect to climate changes. Actually, while the reconstruction of climate fluctuations is by now largely assessed, only a relatively small number of landslides has been dated and only in few cases statistical correlations between climatic changes and landslide oc-currence have been proposed. Nevertheless, the data so far achieved show periods of increasing landslide fre-quency since the retreat of the LGM glaciers which might be reasonably referred to climate changes. The paper then focuses on problems in detecting triggering factors of past landslides and on the limitations given by different persistence of landforms in landscape related to the magnitude/frequency of these events. Moreo-ver, difficulties linked to the dating techniques adopted (including sampling, calibration and correlation of re-sults) are shown. From this point of view, an in-depth knowledge of the principles and limitations of each technique applied and of the geomorphological context in which the instability occurred are of basical im-portance in order to obtain reliable chronostratigraphic data. However, even when all of these items are taken into account, it is still difficult to assess a straightforward relationship between climate changes and landslide occurrence. This is mainly caused by the natural variability of climate in space and time and by the different responses to climatic changes given by the slopes (“slope sensitivity”). Finally, the state of the art on the rela-tionship between landslides and climatic changes in Europe during the Holocene, with particular reference to the most relevant papers dealing with this topic, is described
THE INFLUENCE OF SLOPE DAMAGE ON THE KINEMATICS OF LANDSLIDES
Full text linkThe stability of large rock slopes is controlled by geological, structural, geomorphic, and environmental factors, which define the location, size, and failure mechanism of landslides. However, the stability of a slope can change with time, as a result of the formation and accumulation of slope damage, which weakens the rock mass forming the slope or the rupture surface of the incipient landslide. In this paper, we review three landslide sites, analysing the characteristics of the slope damage, and highlighting its effects on the kinematics of the slope and the evolution of the landslide. We note that, despite the importance of slope damage in controlling the timing and evolution of a slope failure, no frameworks or guidelines currently exist for performing a consistent and systematic analysis. We also emphasize that interdisciplinary approaches should be developed to assist in the quantification and characterization of rock slope damage
Le scienze dell’ingegneria, formazione e opportunità in campo ambientale
Full text linkThe relationship between Engineering Sciences and environmental issues has a long history, but has seen important developments in recent decades, also regarding university education. In this work, the topic is approached from two perspectives. On the one hand, some aspects related to didactics in the academic sphere are examined, and in particular to the experience gained at the University of Bologna with the institution of degree courses in Environmental Engineering. On the other hand, some opportunities offered by the new techniques and technologies for surveying and monitoring the territory are presented, capable of providing new and effective tools for the knowledge and understanding of the environment and ongoing phenomena.La relazione tra le Scienze dell’Ingegneria e le questioni ambientali ha una lunga storia, ma ha visto evoluzioni importanti negli ultimi decenni, anche per quanto concerne la formazione in ambito universitario. In questo lavoro il tema viene affrontato secondo due prospettive. Da un lato, sono esaminati alcuni aspetti legati alla didattica in ambito accademico e in particolare all’esperienza vissuta nell’Università di Bologna con l’istituzione dei corsi di laurea in Ingegneria per l’Ambiente e il Territorio. Dall’altro, sono presentate, a titolo di esempio, alcune opportunità offerte dalle nuove tecniche e tecnologie di rilevamento e monitoraggio del territorio, in grado di fornire strumenti nuovi ed efficaci per la conoscenza e la comprensione dell’ambiente e dei fenomeni in atto
Landslide Recurrence as a Proxy of Climate Change
No full textLandslides and in particular the temporal concentrations of instability events in different periods of the Holocene have not been by now considered as climate proxies, though they could improve significantly the insight of the environmental context as a whole in the reconstructions of past climate changes.The key to answer the questions concerning how and why climate has varied on different time-scales is infact to improve the documentation and understanding of natural variability for periods extending back beyond the instrumental record. Knowledge of past climate changes has to be gained from well-calibrated proxy data derived from different natural archives. These archives should provide accurate records of climate history, should be dated with annual precision on a calendar year time-scale and correlated through time. Actually, no single archive encompasses such properties and information from different sources are to be merged.In this framework, when the geomorphological evolution of a slope can be described by way of surveys, radiometric dating, cross-sections etc., and climate is considered to be the main cause of instability, concentrations of events become significant in a paleoclimatic perspective, if a sufficient number of landslides have been recorded.The records of landslide activity are not likely to be considered as comprehensive proxy archives, but they can give a significant contribution to the establishment of a paleoclimatic multi-proxy database when the environmental context is analysed with a multidisciplinary approach.Within the research carried out in the Dolomites (Italy), the event statigraphy of past landsliding has been traced thanks to the availability of sections and boreholes in which a large number of organic matter samples has been collected and dated with the radiocarbon method.During the Holocene, notwithstanding the evident influence of the geological-structural factors on slope modelling in the study areas, a possible cause-effect relationship between the phases of active slope movements and climatic and environmental changes taking place from the Lateglacial to date can be inferred.A period of enhanced slope instability has been found at the beginning of the Holocene, in the Preboreal and Boreal some 11,500 to 8500 cal yr BP, that reflects the response of the slope-system to the changes in the environmental forcing processes. The retreat of LGM glaciers made the valley flanks sensitive and susceptible of rapid changes and prone to an accelerated geomorphic activity. The response of the slope-system consisted on large rock slides, affecting the dolomite slopes after the withdrawal of Würm glaciers and on complex movements (rotational slides and flows) involving the underlying pelitic formations. A second concentration of landslide events in this area is reported during the Subboreal period (some 5800 to 2000 cal yr BP), when rotational slides and flows mainly took place. The slope movements ascribed to this second phase may likely be considered as reactivations of more ancients events, linked to a humid phase.In any case, the correlation of landslide activity records with the environmental context deduced from other proxies and confirmed by a multidisciplinary approach can validate the assumption that the process of landsliding is an expression of slope-system sensitivity to climate changes
A NEW PERSPECTIVE FOR REGIONAL LANDSLIDE SUSCEPTIBILITY ASSESSMENT
Full text linkLandslides pose a severe geohazard in many countries. The availability of inventories depicting the spatial and temporal distribution of landslides is crucial for assessing landslide susceptibility and risk in territorial planning or investigating landscape evolution. In the case of the Italian territory, several landslide hazard and risk maps were produced ranging from regional to national scale. This was made possible leveraging public domain data of the Italian Landslide Inventory (IFFI project; Trigila et alii, 2010), or other geodatabases spanning from local to regional scale. However, the practical utility of this inventory is often limited in many applications due to its spatial inhomogeneity or the use of different mapping methods and classification criteria. Despite the impressive advancements in techniques for assessing natural hazard susceptibility at a national scale over the past years, including statistical models, AI based models (i.e. Neural Networks) and others, the results are still limited by the quality of the data used. Specifically, the effectiveness of these models is closely tied to the quality of the landslide inventory utilized. Currently, recent regional landslide inventories could potentially enhance precision and accuracy compared to the national dataset, primarily owing to their finer resolution compared to the IFFI dataset. In this work, we present a new approach to assess landslide susceptibility at local scale, relying on regional landslide inventories. Using a data-driven technique, we propose to train a single model on a landslide inventory consisting of a composition of regional inventories selected to be representative of the national scenario. The weighted model is now capable of predicting landslide susceptibility in any study area across Italy. The entire analysis has been done using the SRT tool for Google Earth Engine and the SZ-plugin for QGIS. All the data used and processed are freely available and downloadable. The proposed approach has been tested in the framework of the PNRR RETURN project. The evaluation was conducted in two specific areas: the first one encompasses a section of the railway connecting Napoli to Bari (southern Italy), while the second focuses on areas impacted by the Marche region 2022 landslide event (central Italy). © Author(s). All rights reserved
Multi-temporal analysis of the geomorphic evolution of the failure surface of the Vajont landslide
Full text linkLandslides are among the most common type of hazard that affect mountainous regions. While the impact of the single landslide is often localized and limited to the influence area, in some cases, the occurrence of major events can result in significant and long-lasting social, economic, and environmental impacts that extend beyond the area directly affected by the event. These major landslides involve the sudden detachment of large volumes of rock mass and cause significant disturbance of in-situ stress field due to slope debuttressing and reduction in lateral support, which often result in conditions of limit equilibrium affecting the remaining part of the slope. Effects of such limit equilibrium conditions can range from a long term, gradual morphological evolution of the slope due to progressive detachment of material, to the development of multistage landslides, involving the failure of volumes of rock mass similar in magnitude and impacts to the original event. In this work, we investigate the post-failure morphological evolution of the daylighting rupture surface and deposit of one of the most important historical landslides, the 1963 Vajont Slide. A preliminary investigation of a pair of airborne laser scanner (ALS) datasets, collected in 2017 and 2023, is undertaken to assess and compute the change in elevation across selected areas within the rupture surface. Based on a three-dimensional change detection analysis, the observed volumetric changes of selected, inferred rockfall events are estimated. Terrestrial and airborne photographs are also used to identify the unstable volumes that have progressively detached, as well as the damage features that outlined these unstable blocks. Finally, we discuss the long-term evolution of the slope with focus on progressive damage accumulation and its spatial relationship with inherited, tectonic structures. Ultimately, this contribution is intended to highlight the important role of post-slope failure damage accumulation on the long-term stability of rock slopes, emphasizing the critical role that post-failure monitoring and analysis can play in outlining the residual landslide hazard and, in some instances, the potential development of multi-stage landslides
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