scholarly journals Eighty Years of Data Collected for the Determination of Rainfall Threshold Triggering Shallow Landslides and Mud-Debris Flows in the Alps

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 133 ◽  
Author(s):  
Fabio Luino ◽  
Jerome De Graff ◽  
Anna Roccati ◽  
Marcella Biddoccu ◽  
Chiara Giorgia Cirio ◽  
...  
Keyword(s):  
Debris Flows ◽  
Rainfall Threshold ◽  
Shallow Landslides ◽  
Mean Annual Precipitation ◽  
Economic Damage ◽  
Landslide Risk ◽  
Mountain Areas ◽  
Knowledge Framework ◽  
Rain Gauges ◽  
The Alps

Identifying the minimum rainfall thresholds necessary for landslides triggering is essential to landslide risk assessment. The Italian Alps have always been affected by shallow landslides and mud-debris flows, which caused considerable damage to property and, sometimes, casualties. We analysed information provided from different sources carrying on the most thorough research conducted for this alpine area. Thousands of documents and reports of rainfall values recorded over 80 years by rain gauges distributed in Sondrio and Brescia Provinces define the mean annual precipitation (MAP)-normalized intensity–duration thresholds for the initiation of shallow landslides and mud-debris flows. The established curves are generally lower compared to those proposed in literature for similar mountain areas in Italy and worldwide. Furthermore, we found that landslides occurred primarily at the same time or within 3 h from the maximum peak of rainfall intensity in summer events and in a period from 0 to 5 h or later in spring-autumn events. The paper provides a further contribution to the knowledge framework on the rainfall conditions required for the initiation of surficial landslides and mud-debris flows and their expected timing of occurrence. This knowledge is crucial to develop better warning strategies to mitigate geo-hydrological risk and reduce the socio-economic damage.

scholarly journals Critical rainfall thresholds for triggering shallow landslides in the Serchio River Valley (Tuscany, Italy)

2012 ◽  
Vol 12 (3) ◽  
pp. 829-842 ◽  
Author(s):  
R. Giannecchini ◽  
Y. Galanti ◽  
G. D'Amato Avanzi
Keyword(s):  
Rainfall Threshold ◽  
Shallow Landslides ◽  
River Valley ◽  
Mean Annual Precipitation ◽  
Rainfall Thresholds ◽  
Rain Gauges ◽  
Alarm Systems ◽  
Hourly Rainfall ◽  
Critical Rainfall

Abstract. The Serchio River Valley, in north-western Tuscany, is a well-known tourism area between the Apuan Alps and the Apennines. This area is frequently hit by heavy rainfall, which often triggers shallow landslides, debris flows and debris torrents, sometimes causing damage and death. The assessment of the rainfall thresholds for the initiation of shallow landslides is very important in order to improve forecasting and to arrange efficient alarm systems. With the aim of defining the critical rainfall thresholds for the Middle Serchio River Valley, a detailed analysis of the main rainstorm events was carried out. The hourly rainfall recorded by three rain gauges in the 1935–2010 interval was analysed and compared with the occurrence of shallow landslides. The rainfall thresholds were defined in terms of mean intensity I, rainfall duration D, and normalized using the mean annual precipitation. Some attempts were also carried out to analyze the role of rainfall prior to the damaging events. Finally, the rainfall threshold curves obtained for the study area were compared with the local, regional and global curves proposed by various authors. The results of this analysis suggest that in the study area landslide activity initiation requires a higher amount of rainfall and greater intensity than elsewhere.

Reconstruction of a realistic rainfall field for extreme events happened in mountain area

2021 ◽  
Author(s):  
Andrea Abbate ◽  
Laura Longoni ◽  
Monica Papini
Keyword(s):  
Extreme Events ◽  
Temporal Distribution ◽  
Extreme Rainfall ◽  
Shallow Landslides ◽  
Mountain Areas ◽  
Mountain Area ◽  
Extreme Rainfall Events ◽  
Lombardy Region ◽  
Rain Gauges ◽  
Rainfall Model

<p>In the field of hydrogeological risk, rainfalls represent the most important triggering factor for superficial terrain failures such as shallow landslides, soil slips and debris flow. The availability of local rain gauges measurements is fundamental for defining the cause-effect relationship for predicting failure scenarios. Unfortunately, these hydrogeological phenomena are typical triggered over mountains regions where the density of the ground-based meteorological network is poor, and the local effects caused by mountains topography can change dramatically the spatial and temporal distribution of rainfall. Therefore, trying to reconstruct a representative rainfall field across mountain areas is a challenge but is a mandatory task for the interpretation of triggering causes. We present a reanalysis of an ensemble of extreme rainfall events happened across central Alps and Pre-Alps, in the northern part of Lombardy Region, Italy. We have investigated around some critical aspects such as their intensity and persistency also proposing a modelling of their meteorological evolution, using the Linear Upslope-Rainfall Model (LUM). We have considered this model because it is designed for describing the mechanism of orographic precipitation intensification that was identified as the main cause of that extreme events. To test and calibrate the LUM model we have considered local rain gauges data because they represent the effective rainfall poured on the ground. These punctual data are generally considered for landslide assessment, in particular for rainfall induced phenomena such as shallow landslides and debris flows. Considering our test cases, the results obtained have shown that the LUM has been able to reproduce accurately the rainfall field. In this regard, LUM model can help to address further information around those ungauged area where rainfall estimation could be critical for evaluating the hazard. We are conscious that our and other studies around this topic would be propaedeutic in the next future for the adoption of an integrated framework among the real-time meteorological modelling and the hydrogeological induced risk assessment and prevision.</p>

Towards an early-warning system for rainfall-induced landslides in forested catchments: a case study in Valsassina (Northern Italy)

2020 ◽  
Author(s):  
Michele Placido Antonio Gatto ◽  
Gian Battista Bischetti ◽  
Chiara Miodini ◽  
Lorella Montrasio
Keyword(s):  
Real Time ◽  
Debris Flows ◽  
Early Warning System ◽  
Warning System ◽  
Root Systems ◽  
Northern Italy ◽  
Shallow Landslides ◽  
Landslide Risk ◽  
Physically Based ◽  
Soil Movements

<p>Rainfall-induced soil slips are one of the most common and critical natural phenomena affecting the steep slopes in mountainous regions. These soil processes cause - directly and indirectly - huge damages to human-life, infrastructures and properties, especially when evolve into rapid soil movements such as debris avalanches, debris flows, flow slides, and rockslides. In this context, a landslide risk management that includes an accurate and robust real-time landslide early warning system at large scale (catchment or regional) for assessing the triggering soil slips both in space and in time, is necessary. This purpose appears more complicated where the forest covers most of the territory of a region and landslide-triggering thresholds cannot catch the exact process. In addition, most of physically-based models for real-time landslide warning neglect the role of vegetation, which is well-recognised to be fundamental in preventing shallow soil movements. In fact, forests influence hydrological and mechanical properties of the shallower soil layers through the beneficial effects of root systems and the canopy cover (reducing soil moisture, intercepting precipitation, reinforcing the soil resistance, etc.).</p><p>The present study proposes a modified version of the physically-based stability model, SLIP (Shallow Landslides Instability Prediction), based on the limit equilibrium method applied to an infinite slope and on a simplified modelling of the water down-flow. SLIP was integrated with a quantification of the rainfall interception by the forest canopy, and of the soil reinforcement provided by root systems as a function of tree species and tree density (which are data available from the forest management plans). The adapted model was applied to two mountainous catchments located in Valsassina (Northern Italy) and almost completely covered by forests (conifers, broadleaves and mixed). The study area was affected by shallow landslides and debris flows occurred after extreme meteorological events during autumn 2018. The model accuracy was tested through a back-analysis on the recent soil slips, mapped into a landslide inventory that was produced comparing high-resolution multi-temporal satellite images. The results provide an accurate risk map, identifying the areas of sediments source that can evolve into more threating soil movements.</p><p>The specific development of more accurate physically-based model can reasonably be an important tool for landslide risk management. Combined with a radar rainfall forecasting method, SLIP can be useful for addressing the real-time civil protection response to the emergencies. Moreover, the proposed method can play a key role in identifying the priorities inside the catchment management strategy, e.g. removing accumulated sediments in reservoirs, designing additional geotechnical or soil-bioengineering countermeasures, or evaluating the protection function of the forests.</p>

Debris flow magnitude estimation based on infrasound and seismic signals

2020 ◽  
Author(s):  
Andreas Schimmel ◽  
Matteo Cesca ◽  
Pierpaolo Macconi ◽  
Velio Coviello ◽  
Francesco Comiti
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Warning System ◽  
Early Warning Systems ◽  
Peak Discharge ◽  
Detection Methods ◽  
Mountain Areas ◽  
Detection And Identification ◽  
European Mountain ◽  
The Alps

<p>With the rapid socio-economic development of European mountain areas, the automatic detection and identification of mass movements like landslides, debris flows, and avalanches become more and more important to mitigate related risks by means of early warning systems. Past studies showed that such processes induce characteristic seismic and acoustic signals, the latter mostly in the infrasonic spectrum which can thus be used for event detection. Several investigations have already addressed signal processing and detection methods based on seismic or infrasound sensors. However, for developing an efficient warning system, not only the detection of events is important but also the identification of the event type (e.g. debris flow vs debris flood) and the estimation of its magnitude. So far, no method for such objectives has been developed which is based on the combination of both seismic and infrasonic signals.</p><p>This work presents a first approach to identify debris flows and debris floods magnitude based on the integration of infrasound and seismic data. First analysis shows that, for peak discharge, the use of infrasound amplitudes with a power curve fitting offers a good approach for finding an initial relationship between the recorded signals and this event parameter. For an estimation of the total volume, the discharge calculated with the relationship for peak discharge is integrated over the entire detection time of an event. Calculation of the peak discharge based on infrasound data offers a good approximation, but, for the calculation of the total volume, this method shows still a wide variance.</p><p>The method will be applied to seismic and infrasound data collected on three different test sites in the Alps: Gadria (South Tyrol, Italy), Lattenbach (Tyrol, Austria), and Cancia (Belluno, Italy).</p>

scholarly journals Relationship between rainfall and shallow landslides in the southern Apuan Alps (Italy)

2006 ◽  
Vol 6 (3) ◽  
pp. 357-364 ◽  
Author(s):  
R. Giannecchini
Keyword(s):  
Rainfall Threshold ◽  
Rain Gauge ◽  
Shallow Landslides ◽  
Annual Precipitation ◽  
Hazard Evaluation ◽  
Mean Annual Precipitation ◽  
High Threshold ◽  
Ligurian Sea ◽  
Soil Slip ◽  
Apuan Alps

Abstract. The Apuan Alps region is one of the rainiest areas in Italy (more than 3000 mm/year), in which frequently heavy and concentrated rainfall occurs. This is particularly due to its geographical position and conformation: the Apuan chain is located along the northern Tuscan coast, close to the Ligurian Sea, and the main peaks reach almost 2000 m. In several cases, the storms that hit the area have triggered many shallow landslides (soil slip-debris flows), which exposed the population to serious risks (during the 19 June 1996 rainstorm about 1000 landslides were triggered and 14 people died). The assessment of the rainfall thresholds is very important in order to prepare efficient alarm systems in a region particularly dedicated to tourism and marble activities. With the aim of contributing to the landslide hazard evaluation of the southern Apuan Alps territory (upper Versilia area), a detailed analysis of the main pluviometric events was carried out. The data recorded at the main rain gauge of the area from 1975 to 2002 were analysed and compared with the occurrence of soil slips, in order to examine the relationship between soil slip initiation and rainfall. The most important rainstorms which triggered shallow landslides occurred in 1984, 1992, 1994, 1996, 1998 and 2000. Many attempts were made to obtain a possible correlation between rainfall parameters and the occurrence of soil slip phenomena and to identify the local rainfall threshold for triggering shallow landslides. A threshold for soil slip activity in terms of mean intensity, duration and mean annual precipitation (MAP) was defined for the study area. The thresholds obtained for the southern Apuan Alps were also compared with those proposed by other authors for several regions in the world. This emphasized the high value of the rain threshold for shallow landslide activity in the Apuan area. The high threshold is probably also linked to the high mean annual precipitation and to the high frequency of rainstorms.

scholarly journals Historical Landslide Fatalities in British Columbia, Canada: Trends and Implications for Risk Management

2021 ◽  
Vol 9 ◽  
Author(s):  
Alex Strouth ◽  
Scott McDougall
Keyword(s):  
British Columbia ◽  
Risk Management ◽  
Debris Flows ◽  
Expert Judgment ◽  
Risk Tolerance ◽  
Economic Damage ◽  
Landslide Risk ◽  
Management Measures ◽  
Other World ◽  
Debris Floods

According to a Canadian government database, landslides are the most common type of disaster that occurs in the province of British Columbia. Recently there has been a trend in British Columbia toward using quantitative risk assessments to estimate life-loss risk at landslide hazard sites, and to compare these estimates with risk tolerance thresholds to determine the necessity for, and extent of, risk management measures. These risk estimates are most often calibrated by so-called ‘expert judgment’ because historical landslide fatality data are not readily available. This article addresses this gap by summarizing available historical data to better inform expert judgment. It shows that fatalities caused by landslides in British Columbia are rare (approximately one fatality per year in the last decade) and have decreased with time despite rapid population growth. Approximately half of these fatalities in the last decade are related to debris flows and debris floods that impact houses, whereas the other half are related to rockfalls, debris flows, and debris floods that impact highways. A comparison with other hazard types in the Canadian government’s disaster database suggests that, while not particularly deadly, landslides are still important because of the economic damage and service disruptions they cause. Although the data are specific to British Columbia, the methods for identifying and presenting landslide risk trends could be modified and adopted in other world regions where landslide fatality data are collected and quantitative risk management methods are utilized.

Piemonte. Tra stasi e sperimentazioni, un quadro chiaroscurale / Piedmont. Between stasis and experimentations, a «chiaroscuro» framework

ARCHALP ◽  
2018 ◽  
pp. 66-75
Author(s):  
Antonio De Rossi ◽  
Roberto Dini
Keyword(s):  
Physical Space ◽  
The Other ◽  
Green Economy ◽  
Urban Centers ◽  
Mountain Areas ◽  
Architectural Production ◽  
New Meanings ◽  
The Alps ◽  
Contemporary Situation

The contemporary architectural production in the Alps of Piedmont has to be studied taking into consideration the contrasting phenomena of depopulation and tourism that have involved the mountain areas of the region during last century. In the fifties and sixties the percentage of abandonment of the high valleys reaches even 80-90%. Entire communities move to industrial urban centers in the cities on the plain. On the other side we witness to a strong polarization of the winter stations that become real “banlieues blanches” for the free time of the citizens and where the architecture of alpine modernism, with various forms, shapes. The paradox nowadays is that the rarefaction of abandoned and depopulated territories is necessary to force to start and choose new innovative paths. We witness a contemporary situation with different shades: on one side the well-established touristic territories that need projects to promote the redevelopment and diversification, on the other side the marginal places where are rising new visions are practices of reactivation of the territory in which architecture is fundamental. The topic of quality of the construction of the physical space intersects with the regeneration of places on a cultural basis, new agriculture and green economy, innovative development of the patrimony, sustainable tourism, with inclusive and participative paths of nature, by giving new meanings to places and building new economies and identities.

scholarly journals Debris Flows Occurrence in the Semiarid Central Andes under Climate Change Scenario

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 43
Author(s):  
Stella M. Moreiras ◽  
Sergio A. Sepúlveda ◽  
Mariana Correas-González ◽  
Carolina Lauro ◽  
Iván Vergara ◽  
...  
Keyword(s):  
Climate Change ◽  
Debris Flows ◽  
Environmental Changes ◽  
Urban Expansion ◽  
Central Andes ◽  
Semiarid Region ◽  
Change Scenario ◽  
Permafrost Degradation ◽  
Mountain Areas ◽  
Negative Impacts

This review paper compiles research related to debris flows and hyperconcentrated flows in the central Andes (30°–33° S), updating the knowledge of these phenomena in this semiarid region. Continuous records of these phenomena are lacking through the Andean region; intense precipitations, sudden snowmelt, increased temperatures on high relief mountain areas, and permafrost degradation are related to violent flow discharges. Documented catastrophic consequences related to these geoclimatic events highlight the need to improve their understanding in order to prepare the Andean communities for this latent danger. An amplified impact is expected not only due to environmental changes potentially linked to climate change but also due to rising exposure linked to urban expansion toward more susceptible or unstable areas. This review highlights as well the need for the implementation of preventive measures to reduce the negative impacts and vulnerability of the Andean communities in the global warming context.

Modelling the probability of occurrence of shallow landslides and channelized debris flows using GEOtop-FS

2008 ◽  
Vol 22 (4) ◽  
pp. 532-545 ◽  
Author(s):  
Silvia Simoni ◽  
Fabrizio Zanotti ◽  
Giacomo Bertoldi ◽  
Riccardo Rigon
Keyword(s):  
Debris Flows ◽  
Shallow Landslides ◽  
Probability Of Occurrence

scholarly journals Debris-flow susceptibility assessment through cellular automata modeling: an example from 15–16 December 1999 disaster at Cervinara and San Martino Valle Caudina (Campania, southern Italy)

2003 ◽  
Vol 3 (5) ◽  
pp. 457-468 ◽  
Author(s):  
G. Iovine ◽  
S. Di Gregorio ◽  
V. Lupiano
Keyword(s):  
Cellular Automata ◽  
Debris Flow ◽  
Urban Areas ◽  
Debris Flows ◽  
Soil Cover ◽  
Southern Italy ◽  
Landslide Risk ◽  
Campania Region ◽  
Optimal Values ◽  
Debris Flow Susceptibility

Abstract. On 15–16 December 1999, heavy rainfall severely stroke Campania region (southern Italy), triggering numerous debris flows on the slopes of the San Martino Valle Caudina-Cervinara area. Soil slips originated within the weathered volcaniclastic mantle of soil cover overlying the carbonate skeleton of the massif. Debris slides turned into fast flowing mixtures of matrix and large blocks, downslope eroding the soil cover and increasing their original volume. At the base of the slopes, debris flows impacted on the urban areas, causing victims and severe destruction (Vittori et al., 2000). Starting from a recent study on landslide risk conditions in Campania, carried out by the Regional Authority (PAI –Hydrogeological setting plan, in press), an evaluation of the debris-flow susceptibility has been performed for selected areas of the above mentioned villages. According to that study, such zones would be in fact characterised by the highest risk levels within the administrative boundaries of the same villages ("HR-zones"). Our susceptibility analysis has been performed by applying SCIDDICA S3–hex – a hexagonal Cellular Automata model (von Neumann, 1966), specifically developed for simulating the spatial evolution of debris flows (Iovine et al., 2002). In order to apply the model to a given study area, detailed topographic data and a map of the erodable soil cover overlying the bedrock of the massif must be provided (as input matrices); moreover, extent and location of landslide source must also be given. Real landslides, selected among those triggered on winter 1999, have first been utilised for calibrating SCIDDICA S3–hex and for defining "optimal" values for parameters. Calibration has been carried out with a GIS tool, by quantitatively comparing simulations with actual cases: optimal values correspond to best simulations. Through geological evaluations, source locations of new phenomena have then been hypothesised within the HR-zones. Initial volume for these new cases has been estimated by considering the actual statistics of the 1999 landslides. Finally, by merging the results of simulations, a deterministic susceptibility zonation of the considered area has been obtained. In this paper, aiming at illustrating the potential for debris-flow hazard analyses of the model SCIDDICA S3–hex, a methodological example of susceptibility zonation of the Vallicelle HR-zone is presented.

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