Description and numerical modelling of the October 2000 Nora debris flow, Northwestern Italian Alps

2010 ◽  
Vol 47 (2) ◽  
pp. 135-146 ◽  
Author(s):  
Marina Pirulli ◽  
Federica Marco
Keyword(s):  
Debris Flow ◽  
Depth Distribution ◽  
Alluvial Fan ◽  
Numerical Code ◽  
Rheological Parameters ◽  
Italian Alps ◽  
Debris Slide ◽  
Digital Elevation ◽  
Elevation Model ◽  
Piedmont Region

The Nora alluvial fan, which is located in the Orco River valley (Piedmont region, Italy), was affected by a debris flow of approximately 10 000 m3 in October 2000. The event was triggered by heavy rainfall that affected the whole Piedmont region at that time. The mobilization of the water-satured altered gneissic bedrock and colluvium in the upper zone of the Nora basin resulted in the detachment of a debris slide, which rapidly evolved into a channelized noncohesive debris flow. As information from post-event surveys and two pre-event digital elevation models (DEMs), with different resolutions, were available for the study site, the dynamics of the event has been numerically back-analyzed using the numerical code RASH3D. The obtained results have shown both the capability of the code to simulate the dynamics of a noncohesive debris flow, including the final deposit depth distribution, and the importance of on-site surveys and digital elevation model (DEM) resolution in interpreting numerical results and the associated calibrated rheological parameters.

scholarly journals Fusion Analysis of Optical Satellite Images and Digital Elevation Model for Quantifying Volume in Debris Flow Disaster

2019 ◽  
Vol 11 (9) ◽  
pp. 1096 ◽  
Author(s):  
Hiroyuki Miura
Keyword(s):  
Debris Flow ◽  
Digital Elevation Model ◽  
Large Scale ◽  
Satellite Images ◽  
Erosion Depth ◽  
Digital Elevation ◽  
Elevation Model ◽  
Fusion Analysis ◽  
Optical Satellite Images ◽  
Debris Flow Disaster

Rapid identification of affected areas and volumes in a large-scale debris flow disaster is important for early-stage recovery and debris management planning. This study introduces a methodology for fusion analysis of optical satellite images and digital elevation model (DEM) for simplified quantification of volumes in a debris flow event. The LiDAR data, the pre- and post-event Sentinel-2 images and the pre-event DEM in Hiroshima, Japan affected by the debris flow disaster on July 2018 are analyzed in this study. Erosion depth by the debris flows is empirically modeled from the pre- and post-event LiDAR-derived DEMs. Erosion areas are detected from the change detection of the satellite images and the DEM-based debris flow propagation analysis by providing predefined sources. The volumes and their pattern are estimated from the detected erosion areas by multiplying the empirical erosion depth. The result of the volume estimations show good agreement with the LiDAR-derived volumes.

scholarly journals Numerical Modelling Based on Digital Elevation Model (DEM) Analysis of Debris Flow at Rinjani Volcano, West Nusa Tenggara, Indonesia

2021 ◽  
Vol 7 (3) ◽  
pp. 279
Author(s):  
Muhammad Fatih Qodri ◽  
Noviardi Noviardi ◽  
Al Hussein Flowers Rizqi ◽  
Lindung Zalbuin Mase
Keyword(s):  
Debris Flow ◽  
Digital Elevation Model ◽  
High Speed ◽  
Human Life ◽  
Mass Movement ◽  
High Viscosity ◽  
Particle Flows ◽  
Digital Elevation ◽  
Dem Analysis ◽  
Elevation Model

Debris flow is a disaster occurring in cases where a sediment particle flows at high speed, down to the slope, and usually with high viscosity and speed. This disaster is very destructive and human life-threatening, especially in mountainous areas. As one of the world’s active volcanoes in the world, Rinjani had the capacity to produce over 3 million m3 volume material in the 2015 eruption alone. Therefore, this study proposes a numerical model analysis to predict the debris flow release area (erosion) and deposition, as well as the discharge, flow height, and velocity. The Digital Elevation Model (DEM) was analyzed in ArcGIS, to acquire the Cartesian coordinates and “hillshade” form. This was also used as a method to produce vulnerable areas in the Jangkok watershed. Meanwhile, the Rapid Mass Movement Simulation (RAMSS) numerical modeling was simulated using certain parameters including volume, friction, and density, derived from the DEM analysis results and assumptions from similar historical events considered as the best-fit rheology. In this study, the release volume was varied at 1,000,000 m3, 2,000,000 m3, and 3,000,000 m3, while the simulation results show movement, erosion, and debris flow deposition in Jangkok watershed. This study is bound to be very useful in mitigating debris flow as disaster anticipation and is also expected to increase community awareness, as well as provide a reference for structural requirements, as a debris flow prevention.

scholarly journals Hazard assessment of debris flows for Leung King Estateof Hong Kong by incorporating GIS with numericalsimulations

2004 ◽  
Vol 4 (1) ◽  
pp. 103-116 ◽  
Author(s):  
K. T. Chau ◽  
K. H. Lo
Keyword(s):  
Hong Kong ◽  
Debris Flow ◽  
Numerical Simulations ◽  
Computer Simulations ◽  
Debris Flows ◽  
Potential Hazard ◽  
Expert Opinions ◽  
Flow Parameters ◽  
Digital Elevation ◽  
Elevation Model

Abstract. As over seventy percent of the land of Hong Kong is mountainous, rainfall-induced debris flows are not uncommon in Hong Kong. The objective of this study is to incorporate numerical simulations of debris flows with GIS to identify potential debris flow hazard areas. To illustrate this approach, the proposed methodology is applied to Leung King Estate in Tuen Mun. A Digital Elevation Model (DEM) of the terrain and the potential debris-flow sources were generated by using GIS to provide the required terrain and flow source data for the numerical simulations. A theoretical model by Takahashi et al. (1992) improved by incorporating a new erosion initiation criterion was used for simulating the runout distances of debris flows. The well-documented 1990 Tsing Shan debris flow, which occurred not too far from Leung King Estate, was used to calibrate most of the flow parameters needed for computer simulations. Based on the simulation results, a potential hazard zone was identified and presented by using GIS. Our proposed hazard map was thus determined by flow dynamics and a deposition mechanism through computer simulations without using any so- called expert opinions, which are bounded to be subjective and biased.

A Paleoenvironmental Reconstruction of Elkwater Lake, Alberta

2004 ◽  
Vol 56 (2-3) ◽  
pp. 279-290 ◽  
Author(s):  
Dion J. Wiseman ◽  
Garry L. Running ◽  
Andrea Freeman
Keyword(s):  
Late Holocene ◽  
Alluvial Fan ◽  
Water Levels ◽  
Paleoenvironmental Reconstruction ◽  
Lake Levels ◽  
Mass Wasting ◽  
The West ◽  
Digital Elevation ◽  
Lake Formation ◽  
Elevation Model

AbstractCores retrieved from two slump blocks at the west end of Elkwater Lake, Alberta were used to determine which of two mass wasting events was responsible for impounding the lake and to establish a maximum age of lake formation. A high resolution Digital Elevation Model of the study area was used to estimate the volume of material involved in each mass wasting event, recreate pre-slump topographic conditions, determine the probable extent and elevation of the lake at different periods in time, and evaluate the viability of alternative outlets. Results suggest that the lake formed no more than 9440 BP as a result of impoundment by the eastern slump block. The lake rose to its highest mid-Holocene elevation prior to 7245 BP, establishing an outlet through Feleski Creek 3.5 km northeast of the present shoreline. Lake levels then dropped during the comparatively dry Altithermal, concurrent with a period of rapid sediment influx and the development of the alluvial fan on which the Stampede site is located. As water levels rose during the late Holocene, and with the former outlet cut off by progradation of the alluvial fan, Elkwater Lake established its present outlet though Ross Creek.

scholarly journals Modeling and Classification of Alluvial Fans with DEMs and Machine Learning Methods: A Case Study of Slovenian Torrential Fans

2021 ◽  
Vol 13 (9) ◽  
pp. 1711
Author(s):  
Matej Babič ◽  
Dušan Petrovič ◽  
Jošt Sodnik ◽  
Božo Soldo ◽  
Marko Komac ◽  
...  
Keyword(s):  
Machine Learning ◽  
Debris Flow ◽  
Human Life ◽  
Alluvial Fans ◽  
Digital Elevation ◽  
Elevation Model ◽  
Flow Activity ◽  
Geomorphometric Parameters

Alluvial (torrential) fans, especially those created from debris-flow activity, often endanger built environments and human life. It is well known that these kinds of territories where human activities are favored are characterized by increasing instability and related hydrological risk; therefore, treating the problem of its assessment and management is becoming strongly relevant. The aim of this study was to analyze and model the geomorphological aspects and the physical processes of alluvial fans in relation to the environmental characteristics of the territory for classification and prediction purposes. The main geomorphometric parameters capable of describing complex properties, such as relative fan position depending on the neighborhood, which can affect their formation or shape, or properties delineating specific parts of fans, were identified and evaluated through digital elevation model (DEM) data. Five machine learning (ML) methods, including a hybrid Euler graph ML method, were compared to analyze the geomorphometric parameters and physical characteristics of alluvial fans. The results obtained in 14 case studies of Slovenian torrential fans, validated with data of the empirical model proposed by Bertrand et al. (2013), confirm the validity of the developed method and the possibility to identify alluvial fans that can be considered as debris-flow prone.

scholarly journals Predicting storm triggered debris flow events: application to the 2009 Ionian-Peloritan disaster (Sicily, Italy)

2015 ◽  
Vol 3 (3) ◽  
pp. 1731-1774
Author(s):  
M. Cama ◽  
L. Lombardo ◽  
C. Conoscenti ◽  
R. Rotigliano
Keyword(s):  
Debris Flow ◽  
Binary Logistic Regression ◽  
Stochastic Modelling ◽  
Storm Events ◽  
M Cell ◽  
Small Catchment ◽  
Digital Elevation ◽  
Susceptibility Model ◽  
Geologic Map ◽  
Elevation Model

Abstract. The main assumption on which landslide susceptibility assessment by means of stochastic modelling lays is that the past is the key to the future. As a consequence, a stochastic model able to classify a past known landslide scenario should be able to predict a future unknown one as well. However, storm triggered landslide events in the Mediterranean region could pose some limits on the operative validity of such expectation, as they typically result by a randomness in time recurrence and magnitude. This is the case of the 2007/09 couple of storm events, which recently hit north-eastern Sicily resulting in largely different disaster scenarios. The purpose of this study is to test whether a susceptibility model based on stepwise binary logistic regression is able to predict a storm triggered debris flow scenario. The study area is the small catchment of the Itala torrent (10 km2), which drains from the southern Peloritan Mountains eastward to the Ionian sea, in the province of the Messina territory (Sicily, Italy). The shallow landslides activated in the occasion of two close intense rainfall events have been mapped by integrating remote and field surveys, producing two event inventories which include 73 landslides, activated in 2007, and 616 landslides, triggered by the 2009 storm. The set of predictors were derived from a 2 m cell digital elevation model and a 1 : 50 000 scale geologic map. The topic of the research was explored by performing two types of validation procedures: self-validation, based on the random partition of each event inventory and chrono-validation, based on the time partition of the landslide inventory. It was therefore possible to analyse and compare the performances both of the 2007-calibrated model in predicting the 2009 landslides (forward chronovalidation) and vice versa of the 2009-calibrated model in predicting the 2007 landslides (backward chronovalidation). Both the two predictions resulted in largely acceptable performances, in terms of fitting, skill and reliability. However, a loss of performance and differences in the selected predictors between the self-validated and the chrono-validated models which are linked to the characteristics of the two triggering storms are highlighted.

Simplified simulation of rock avalanches and subsequent debris flows with a single thin-layer model. Application to the Prêcheur river (Martinique, Lesser Antilles)

2021 ◽  
Author(s):  
Marc Peruzzetto ◽  
Clara Levy ◽  
Yannick Thiery ◽  
Gilles Grandjean ◽  
Anne Mangeney ◽  
...  
Keyword(s):  
Debris Flow ◽  
Thin Layer ◽  
Debris Flows ◽  
Initial Conditions ◽  
Rock Avalanche ◽  
Numerical Code ◽  
Lesser Antilles ◽  
Rheological Parameters ◽  
Model Parameters ◽  
High Discharge

<p>This work focuses on the use of thin-layer models for simulating fast gravitational flows for hazard assessment. Such simulations are sometimes difficult to carry out because of the uncertainty on initial conditions and on simulation parameters. In this study, we aggregate various field data to constrain realistic initial conditions and to calibrate the model parameters. By using the SHALTOP numerical code, we choose a simple and empirical rheology to model the flow (no more than two parameters), but we model more finely the geometrical interactions between the flow and the topography. We can thus model both a rock avalanche, and the subsequent remobilization of the deposits as a high discharge debris flow.</p><p>Using the Prêcheur river catchment (Martinique, Lesser Antilles) as a case study, we focus on extreme events with a high potential to impact populations and infrastructures. We use geological and geomorphological data, topographic surveys, seismic recordings and granulometric analysis to define realistic simulation scenarios and determine the main characteristics of documented events. The latter are then reproduced to calibrate rheological parameters. With a single rheological parameter and the Coulomb rheology, we thus model the emplacement and main dynamic characteristics of a recent rock avalanche, as well as the travel duration and flooded area of a documented high discharge debris flow. Then, in a forward prediction simulation, we model a possible 1.9x10<sup>6 </sup>m<sup>3</sup> rock avalanche, and the instantaneous remobilization of the resulting deposits as a high-discharge debris flow. We show that successive collapses allow to better reproduce the dynamics of the rock avalanche, but do not change the geometry of the final deposits, and thus do not influence the initial conditions of the subsequent debris flow simulation. A progressive remobilization of the materials slows down the debris flow and limits overflow, in comparison to instantaneous release. However, we show that high discharge debris flows, such as the one considered for model calibration, are better reproduced with an instantaneous initiation. The range of travel times measured for other significant debris flows in the Pr\^echeur river is consistent with our simulation results, with various rheological parameters and the Coulomb or Voellmy rheology.</p>

scholarly journals Assessing potential debris flow runout: a comparison of two simulation models

2008 ◽  
Vol 8 (4) ◽  
pp. 961-971 ◽  
Author(s):  
M. Pirulli ◽  
G. Sorbino
Keyword(s):  
Debris Flow ◽  
Back Analysis ◽  
Simulation Models ◽  
Numerical Code ◽  
Rheological Parameters ◽  
Rheological Parameter ◽  
Safe Side ◽  
Study Sites ◽  
Comparison Of The Results ◽  
Parameter Values

Abstract. In the present paper some of the problems related to the application of the continuum mechanics modelling to debris flow runout simulation are discussed. Particularly, a procedure is proposed to face the uncertainties in the choice of a numerical code and in the setting of rheological parameter values that arise when the prediction of a debris flow propagation is required. In this frame, the two codes RASH3D and FLO2D are used to numerically analyse the propagation of potential debris flows affecting two study sites in Southern Italy. For these two study sites, a lack in information prevents that the rheological parameters can be obtained from the back analysis of similar well documented debris flow events in the area. As a prediction of the possible runout area is however required by decision makers, an alternative approach based on the analysis of the alluvial fans existing at the toe of the two studied basins is proposed to calibrate rheological parameters on the safe side. From the comparison of the results obtained with RASH3D (where a Voellmy and a Quadratic rheologies are implemented) and FLO2D (where a Quadratic rheology is implemented) it emerges that, for the two examined cases, numerical analyses carried out with RASH3D assuming a Voellmy rheology can be considered on the safe side respect to those carried out with a Quadratic rheology.

scholarly journals The use of FLO2D numerical code in lahar hazard evaluation at Popocatépetl volcano: a 2001 lahar scenario

2014 ◽  
Vol 14 (12) ◽  
pp. 3345-3355 ◽  
Author(s):  
L. Caballero ◽  
L. Capra
Keyword(s):  
Rheological Properties ◽  
Numerical Code ◽  
Hazard Evaluation ◽  
Digital Elevation ◽  
Popocatépetl Volcano ◽  
Elevation Model ◽  
Definition Of ◽  
Digital Elevation Model Resolution ◽  
Excellent Tool ◽  
Popocatepetl Volcano

Abstract. Lahar modeling represents an excellent tool for designing hazard maps. It allows the definition of potential inundation zones for different lahar magnitude scenarios and sediment concentrations. Here, we present the results obtained for the 2001 syneruptive lahar at Popocatépetl volcano, based on simulations performed with FLO2D software. An accurate delineation of this event is needed, since it is one of the possible scenarios considered if magmatic activity increases its magnitude. One of the main issues for lahar simulation using FLO2D is the calibration of the input hydrograph and rheological flow properties. Here, we verified that geophone data can be properly calibrated by means of peak discharge calculations obtained by the superelevation method. Digital elevation model resolution also resulted as an important factor in defining the reliability of the simulated flows. Simulation results clearly show the influence of sediment concentrations and rheological properties on lahar depth and distribution. Modifying rheological properties during lahar simulation strongly affects lahar distribution. More viscous lahars have a more restricted aerial distribution and thicker depths, and resulting velocities are noticeably smaller. FLO2D proved to be a very successful tool for delimitating lahar inundation zones as well as generating different lahar scenarios not only related to lahar volume or magnitude, but also taking into account different sediment concentrations and rheologies widely documented as influencing lahar-prone areas.

scholarly journals Using a fixed-wing UAS to map snow depth distribution: an evaluation at peak accumulation

2016 ◽  
Vol 10 (2) ◽  
pp. 511-522 ◽  
Author(s):  
Carlo De Michele ◽  
Francesco Avanzi ◽  
Daniele Passoni ◽  
Riccardo Barzaghi ◽  
Livio Pinto ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Snow Depth ◽  
Depth Distribution ◽  
Aerial Survey ◽  
Preliminary Evaluation ◽  
Spatial Integration ◽  
Rotor Systems ◽  
Digital Elevation ◽  
Elevation Model

Abstract. We investigate snow depth distribution at peak accumulation over a small Alpine area ( ∼  0.3 km2) using photogrammetry-based surveys with a fixed-wing unmanned aerial system (UAS). These devices are growing in popularity as inexpensive alternatives to existing techniques within the field of remote sensing, but the assessment of their performance in Alpine areas to map snow depth distribution is still an open issue. Moreover, several existing attempts to map snow depth using UASs have used multi-rotor systems, since they guarantee higher stability than fixed-wing systems. We designed two field campaigns: during the first survey, performed at the beginning of the accumulation season, the digital elevation model of the ground was obtained. A second survey, at peak accumulation, enabled us to estimate the snow depth distribution as a difference with respect to the previous aerial survey. Moreover, the spatial integration of UAS snow depth measurements enabled us to estimate the snow volume accumulated over the area. On the same day, we collected 12 probe measurements of snow depth at random positions within the case study to perform a preliminary evaluation of UAS-based snow depth. Results reveal that UAS estimations of point snow depth present an average difference with reference to manual measurements equal to −0.073 m and a RMSE equal to 0.14 m. We have also explored how some basic snow depth statistics (e.g., mean, standard deviation, minima and maxima) change with sampling resolution (from 5 cm up to  ∼  100 m): for this case study, snow depth standard deviation (hence coefficient of variation) increases with decreasing cell size, but it stabilizes for resolutions smaller than 1 m. This provides a possible indication of sampling resolution in similar conditions.

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