scholarly journals The Role of Initial Soil Conditions in Shallow Landslide Triggering: Insights from Physically Based Approaches

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
L. Schilirò ◽  
G. Poueme Djueyep ◽  
C. Esposito ◽  
G. Scarascia Mugnozza
Keyword(s):  
Central Italy ◽  
Shallow Landslide ◽  
Rainfall Event ◽  
Soil Conditions ◽  
Initial Water Content ◽  
Extreme Rainfall Event ◽  
Wetting Front ◽  
Clayey Sand ◽  
Physically Based

In the last years, the shallow landslide phenomenon has increasingly been investigated through physically based models, which try to extend over large-area simplified slope stability analyses using physical and mechanical parameters of the involved material. However, the parameterization of such models is usually challenging even at the slope scale, due to the numerous parameters involved in the failure mechanism. In particular, considering the scale of the phenomenon, the role of transient hydrology is essential. For this reason, in this work we present the outcome of different experimental tests conducted on a soil slope model with a sloping flume. The tested material was sampled on Monte Mario Hill (Rome, Central Italy), an area which has been frequently affected by rainfall-induced landslide events in the past. In this respect, we also performed a physically based numerical analysis at the field conditions, in order to evaluate the response of the terrain to a recent extreme rainfall event. The results of the flume tests show that, for the same material, two different triggering mechanisms (i.e., uprise of a temporary water table and advance of the wetting front) occur by varying the initial water content only. At the same time, the results of the numerical simulations indicate that clayey sand and lean clay are the soil types mostly influenced by the abovementioned rainfall event, since the initial moisture conditions enhance the formation of a wide wetting front within the soil profile.

scholarly journals Distributed modelling of shallow landslides triggered by intense rainfall

2003 ◽  
Vol 3 (1/2) ◽  
pp. 81-93 ◽  
Author(s):  
G. B. Crosta ◽  
P. Frattini
Keyword(s):  
Model Performance ◽  
Radar Data ◽  
Shallow Landslides ◽  
Rainfall Event ◽  
Distributed Model ◽  
Hydrological Models ◽  
Wetting Front ◽  
Diffusive Model ◽  
Physically Based ◽  
Landslide Triggering

Abstract. Hazard assessment of shallow landslides represents an important aspect of land management in mountainous areas. Among all the methods proposed in the literature, physically based methods are the only ones that explicitly includes the dynamic factors that control landslide triggering (rainfall pattern, land-use). For this reason, they allow forecasting both the temporal and the spatial distribution of shallow landslides. Physically based methods for shallow landslides are based on the coupling of the infinite slope stability analysis with hydrological models. Three different grid-based distributed hydrological models are presented in this paper: a steady state model, a transient "piston-flow" wetting front model, and a transient diffusive model. A comparative test of these models was performed to simulate landslide occurred during a rainfall event (27–28 June 1997) that triggered hundreds of shallow landslides within Lecco province (central Southern Alps, Italy). In order to test the potential for a completely distributed model for rainfall-triggered landslides, radar detected rainfall intensity has been used. A new procedure for quantitative evaluation of distributed model performance is presented and used in this paper. The diffusive model results in the best model for the simulation of shallow landslide triggering after a rainfall event like the one that we have analysed. Finally, radar data available for the June 1997 event permitted greatly improving the simulation. In particular, radar data allowed to explain the non-uniform distribution of landslides within the study area.

scholarly journals Comparison between different approaches to modeling shallow landslide susceptibility: a case history in Oltrepo Pavese, Northern Italy

2013 ◽  
Vol 13 (3) ◽  
pp. 559-573 ◽  
Author(s):  
D. Zizioli ◽  
C. Meisina ◽  
R. Valentino ◽  
L. Montrasio
Keyword(s):  
Shallow Landslide ◽  
Northern Italy ◽  
Shallow Landslides ◽  
Rainfall Event ◽  
Aerial Photographs ◽  
Intense Rainfall ◽  
Field Surveys ◽  
Ex Post ◽  
Physically Based ◽  
Physically Based Models

Abstract. On the 27 and 28 April 2009, the area of Oltrepo Pavese in northern Italy was affected by a very intense rainfall event that caused a great number of shallow landslides. These instabilities occurred on slopes covered by vineyards or recently formed woodlands and caused damage to many roads and one human loss. Based on aerial photographs taken immediately after the event and field surveys, more than 1600 landslides were detected. After acquiring topographical data, geotechnical properties of the soils and land use, susceptibility analysis on a territorial scale was carried out. In particular, different physically based models were applied to two contiguous sites with the same geological context but different typologies and sizes of shallow landslides. This paper presents the comparison between the ex-post results obtained from the different approaches. On the basis of the observed landslide localizations, the accuracy of the different models was evaluated, and the significant results are highlighted.

scholarly journals Shallow landslides involving weathered and fractured bedrock: a comparative susceptibility analysis between deterministic and statistical models

2020 ◽  
Author(s):  
Enrico D'Addario ◽  
Leonardo Disperati ◽  
José Luís Zêzere ◽  
Raquel De Melo ◽  
Sérgio Oliveira
Keyword(s):  
Statistical Models ◽  
Regional Scale ◽  
Central Italy ◽  
Shallow Landslide ◽  
Geological Strength Index ◽  
Predictive Capacity ◽  
Predisposing Factor ◽  
Fractured Bedrock ◽  
Susceptibility Analysis ◽  
Physically Based

<p>Shallow landslide susceptibility modelling at regional scale may be performed using both a physically based and statistical approach. For the same area, these two approaches can have inconsistent results, mainly because the two methods are conceptually different. Physically based models are based on the infinite slope model and consists on the computation cell by cell of a safety factor comparing between driving and resisting forces. The assumption that landslides occur in slopes that are characterized by predisposing factors similar to those in which landslides have occurred in the past, is the concept behind the statistical models. The aim of this work is to compare the two approach and investigate the differences between the two models. The study area is located in northern Tuscany, central Italy, in which an extensive field survey highlighted that about 60% of landslides involve bedrock. For this reason, we developed a physically based susceptibility analysis taking into account both the surficial layer (slope deposit, SD) and the underlying layer (BR), characterized by weathered and fractured bedrock. This model is compared to the statistically based one, which take into account topographic and geologic predisposing factor as well as bedrock geo-mechanical properties, such Geological Strength Index (GSI), Schmidt hammer rebound values (Rv) and Joint density (Jv). The accuracy of the models is evaluated using a multi-temporal landslide inventory, in which involving bedrock landslides are distinct from slope deposits landslides. Within this general framework results are discussed regarding the model’s predictive capacity and spatial agreement.</p>

scholarly journals Numerical Simulations of the 2013 Alberta Flood: Dynamics, Thermodynamics, and the Role of Orography

2017 ◽  
Vol 145 (8) ◽  
pp. 3049-3072 ◽  
Author(s):  
Shawn M. Milrad ◽  
Kelly Lombardo ◽  
Eyad H. Atallah ◽  
John R. Gyakum
Keyword(s):  
Extreme Rainfall ◽  
Rainfall Event ◽  
Extreme Rainfall Event ◽  
Canadian History ◽  
Mesoscale Dynamics ◽  
Physical Mechanisms ◽  
Long Duration ◽  
Surface Cyclone ◽  
Flood Dynamics

The 19–21 June 2013 Alberta flood was the second costliest ($6 billion CAD) natural disaster in Canadian history, trailing only the 2016 Fort McMurray, Alberta, Canada, wildfires. One of the primary drivers was an extreme rainfall event that resulted in 75–150 mm of precipitation in the foothills west of Calgary, Canada. Here, the mesoscale dynamics and thermodynamics that contributed to the extreme rainfall event are elucidated through high-resolution numerical model simulations. In addition, terrain reduction model sensitivity experiments using Gaussian smoothing techniques quantify the importance of orography in producing the extreme rainfall event. It is suggested that the extreme rainfall event was initially characterized by the formation of a surface cyclone on the eastern side of the Canadian Rockies due to quasigeostrophic (QG) mechanisms. Orographic processes and diabatic heating feedbacks maintained the surface cyclone throughout the event, extending the duration of both easterly upslope flow and QG forcing for ascent in the flood region. The long-duration ascent and associated condensational heat release in the flood region vertically redistributed potential vorticity, anchoring and further extending the duration of the surface cyclone, upslope flow, and the rainfall. Although the magnitudes of ascent and precipitation were smaller in 10% and 25% reduced terrain simulations, only a terrain reduction of greater than 25% drastically altered the location and magnitude of the heaviest precipitation and the associated physical mechanisms.

scholarly journals Elucidating the role of vegetation in the initiation of rainfall-induced shallow landslides: Insights from an extreme rainfall event in the Colorado Front Range

2016 ◽  
Vol 43 (17) ◽  
pp. 9084-9092 ◽  
Author(s):  
Luke A. McGuire ◽  
Francis K. Rengers ◽  
Jason W. Kean ◽  
Jeffrey A. Coe ◽  
Benjamin B. Mirus ◽  
...  
Keyword(s):  
Extreme Rainfall ◽  
Shallow Landslides ◽  
Rainfall Event ◽  
Colorado Front Range ◽  
Extreme Rainfall Event ◽  
Front Range
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