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A complete model for landslides prediction. Validation for the analysis of infiltration processes in pyroclastic soils
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Development of an hydrological landslide model at regional scale. Applications in the central part of Calabria region (southern Italy)
No full textIn the last years, many hydrogeological emergencies,
induced by persistent and widespread rainfall events,
concerned Calabria region (southern Italy), in particular during
the winter season. Flood and landslide events undermined the
safety of tens of thousands of people. These events, related to
the period 2008-2010, are comparable, or even worse, with
those occurred in the 50’s and in the early 70’s.
The proposed study regards the analysis of triggering
conditions for landslides induced by rainfall. For this topic,
many models are reported in the technical literature, which
allow the definition of instability conditions for a slope,
through an accurate investigation. (MONTGOMERY & DIETRICH,
1994; IVERSON, 2000; GUZZETTI, 2008; CEPEDA et al., 2010).
In particular, this work describes an hydrological approach
for the trigger modeling of landslides, and the applications
related to the provinces of Catanzaro, Vibo Valentia and
Crotone.
For each investigated province, a lot of landslide events
have been documented, characterized by different kinematic,
lithological and morphological conditions, but the same
triggering factor, the rainfall.
The analysis was carried out by using the hydrological
model named FLaIR (Forecasting of Landslides Induced by
Rainfalls, SIRANGELO & VERSACE, 1992), for which some
improvements were realized in the last years.
Each landslide area was investigated, and then
regionalization techniques were developed, aimed at the
definition of transfer functions, parameters and rainfall
thresholds representative of each province.
The obtained results allow to apply the FLaIR model also in
areas characterized by a lack of information for the past
mobilization events
Shallow landslides risk mitigation by early warning: the case of the 1998 mudslides of Sarno
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Physical modeling investigation of rainfall infiltration in steep layered volcanoclastic slopes
No full textInfiltration processes in layered slopes can be strongly affected by the different hydraulic properties of the soils constituting the layers, with potential downslope flow diversion that can have effects on slope stability as well as on runoff generation and groundwater recharge. In this respect, volcanoclastic soil covers represent a typical example, as layers with strongly contrasting textures are deposited during the various eruptive phases. In this paper, the results of a transient infiltration test, carried out in a densely instrumented physical model of a layered volcanoclastic sloping cover, are presented. The soil cover was constituted by a layer of gravelly pumices interbedded between two layers of finer ashes (sandy loams). Even with such an extreme contrast in texture, capable of significantly delaying the advancement of infiltration through the layer of pumices, flow diversion occurred only temporarily at the interface between the upper layer of ashes and the pumices. In fact, although a long-lasting intense rainfall was applied into an initially dry soil profile, the downslope diverted water volume in form of a subsurface runoff was just a small fraction of the total applied rainfall. In fact, the accumulation of water above the upper edge of the pumices, responsible of the subsurface runoff, soon led to the establishment of a large water potential gradient, which redirected the infiltrating flow through the pumices and stopped the downslope flow diversion
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
Formulation of landslide risk scenarios using underground monitoring data and numerical models: conceptual approach, analysis, and evolution of a case study in Southern Italy
No full textUnderstanding the mechanism of a landslide and its evolution is of fundamental importance in the risk management process. This work introduces an articulated approach to the problem, applying it to a specific case in the south of Italy where a gravitational movement insists on a section of an important highway. In recent years, the site has been investigated from a geomorphological and a lithological point of view, and a comprehensive geomechanical characterization has been carried out by means of on-site and laboratory tests. The area has been instrumented with a monitoring system composed of automatic inclinometers, piezometers, a rainfall station, and time domain reflectometry (TDR) cables. These sensors have monitored the deformation processes and their correlation with groundwater fluctuation. A 2D finite differences model (FDM) of the slope has been created, calibrated, and validated through back analysis, carried out using the monitoring data available. A secondary creep phenomenon, barely influenced by the water level rise due to occasional rainfall, has been identified and modeled using the Burgers viscoelastic constitutive model. Variations in the piezometric level were introduced and their effect accounted for the numerical model refinement. Once the improvements had been completed together with the reproduction of past events, a predictive analysis was carried out in order to forecast the most probable slope behavior relative to the incoming year. At the end of this phase, the infrastructure supervisor should have information about possible deformations to be compared with the near real-time monitoring outcomes and design assumptions. This procedure allows real-time monitoring of the compatibility of slope deformations with highway safety
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