All posts by Jérémie Voumard

Jérémie Voumard: “Natural hazards affecting the Swiss transportation networks: from their characterization to their low cost survey”

Jérémie Voumard
Director: Prof. Dr. Michel Jaboyedoff
Jury: Dr. Marc-Henri Derron, Dr. Andrea Pedrazzini, Dr. Nicolas Pollet, Prof. Dr. Suren Erkmann

Geological and hydro-geological natural hazards, as landslides and floods, are a threat to many transport networks built in mountainous areas. These risks, that are often small in intensity, are poorly evaluated or unknown.
This doctoral thesis focuses on the characterization and quantification of natural hazards that impact Swiss communication tracks. It also explores various remote sensing techniques dedicated to the survey of areas around traffic lanes.
A database has been created to characterize the many small events that regularly affect roads and railway lines in order to compensate the lack of knowledge. The number of events and their trends – such as their spatio-temporal distribution, the weather, the geology, the direct damages or the types of affected tracks- are thus known at the national level over a period of five years (2012-2016). It shows that a natural event, on average, disrupts the traffic every 2.1 days and that the events occur mostly during the months of June and July, late afternoon. Direct costs were estimated at CHF 4 million per year, with an average cost per event estimated at 23 400 francs.
In order to characterize the approaches to roads and railways, we have developed and tested the photogrammetric technique “on-motion Structure from Motion”, whose cost is reasonable. This remote sensing technic makes possible to obtain colorized and georeferenced 3D point clouds from images taken by four action cameras placed on a moving vehicle. Its accuracy has been evaluated in laboratory conditions and on many sites. It was also compared with seven other traditional surveillance techniques to identify advantages and disadvantages.
This work highlights the impact and consequences of small-scale natural hazards that, taken as a whole, are not negligible for society. In addition, this study demonstrates that low-cost survey technic can compete with more expensive traditional survey techniques.

Keywords: Natural hazards, transportation networks, on-motion Structure for Motion, topographical survey.

3D modelling the oak of Napoléon

The Risk group participed in a study conducted by researchers at the University of Lausanne whose results where published in Nature Plants . Results reveal that the genome of oak Napoleon has evolved little during its first 234 years of existence.

The 3D modelling was carry out using a LiDAR. Terrestrial LiDAR scans were taken around the oak every 60°. The six scans were cleaned from background objects and aligned in order to generate a 1.2 million 3D-points cloud. The mesh from the 3D points cloud was colourized to produce the final 3D oak model.

Sources: Nature Plants, Le Temps, 24Heures, News Unil, Napoleome

Oak of Napoleon from our automatic camera along seasons:

Oak scanning:

3D-printed model of the oak:

Near-infrared image of the oak:

Flight at Bondo (GR)

Five people of the Risk Analysis Group went to Bondo, Canton of Graubünden, on 29 September 2017 to make a helicopter flight along the debris flow and cliff collapse of the August event. During a 25 minutes flight from the village of Bondo to the Piz Cengalo through the Val Bondasca, 11’400 pictures were taken by automatically and manually operated cameras . Those data will be used to get 3D models of the area by SfM processing.

 

Risk group @ EGU 2017 in Vienna

The Risk Group participated to the European Geosciences Union (EGU) General Assembly in Vienna, Austria, on 17 April to 22 May 2017. This huge meeting brought together 14’496 scientists from 107 countries with 4’849 orals, 11’312 posters and 1’238 PICO presentations.

It is always an excellent opportunity for our group to meet new people and other scientists we work with during the five days of the meeting. The Risk Group people presented 30 contributions as first authors whose titles are below.

4 orals:

  • Rockfall travel distances theoretical distributions Michel Jaboyedoff et al.
  • Rockfall monitoring of a poorly consolidated marly sandstone cliff by TLS and IR thermography Caroline Lefeuvre et al.
  • Characterization of the deformation and thermal behavior of granitic exfoliation sheets with LiDAR and infrared thermography (Yosemite Valley, USA) Antoine Guerin et al.
  • Optimizing the use of airborne LiDAR data for a better analysis and communication of 3D results​ François Noël et al.

4 PICO:

  • Debris flows susceptibility mapping under tropical rain conditions in Rwanda.
    Emmanuel Nduwayezu et al.
  • Five years database of landslides and floods affecting Swiss transportation networks Jérémie Voumard et al.
  • Three consecutive years of road closures due to natural hazards in the Weisstannen valley, Canton of St-Gallen, Switzerland Jérémie Voumard et al.
  • Experimental insights of liquid impacts onto granular beds of various packings : The packing influence over the excavated volumes Emmanuel Wyser et al.

9 posters:

  • Integrated risk management and communication: case study of Canton Vaud (Switzerland) Veronica Artigue et al.
  • Radiometric enhancements of thermal infrared images for rock slope investigation by coupling with groundbased LiDAR Marc-Henri Derron et al.
  • Landslide-Generated Tsunami model Martin Franz et al.
  • Introducing a moving time window in the analogue method for precipitation prediction to find better analogue situations at a sub-daily time step Pascal Horton et al.
  • Using genetic algorithms to achieve an automatic and global optimization of analogue methods for statistical downscaling of precipitation Pascal Hortonet al.
  • Development of a 3D rockfall simulation model for point cloud topography
    François Noël et al.
  • Understanding three decades of land use changes and a cloudburst in Phewa Lake Watershed, Western Nepal Karen Sudmeier-Rieux et al.
  • Automatic 3D relief acquisition and georeferencing of road sides by low-cost on-motion SfM Jérémie Voumard et al.
  • Preliminary 2D numerical modeling of common granular problems Emmanuel Wyser et al.

Risk group @ RocExs 2017 – Barcelona

The Risk Group participated to 6th Interdisciplinary Workwhop on Rockfall Protection in Barcelona, Spain, on 22-24 May 2017.
The first two days, we followed the different presentations while the third day, we participated to a field trip in the Monserrat Massif whose theme was dedicated to rockfall management.
Presentations from the Risk Group:
  • 11 years of ground-based LiDAR monitoring in the West Face of the Drus (Mont-Blanc Massif, France) after the little rock avalanche of June 2005. Guerin et al.
  • The effect of slope roughness on 3D rockfall simulation results. Noël et al.
  • Multi-technique approach to assess rockfall propagation: a case study from Les Forges, Jura, Switzerland. Lefeuvre et al.

Risk group at the 12th International Symposium on Landslides (ISL)

Four persons of the Risk Group participated to the 12th International Symposium on Landslides (ISL) in Napoli, Italy, on 12 to 19 June 2016. We presented one lecture and three orals. All contributions at the symposium are collected into three books.
It was a great opportunity for us to meet scientists we work with during the five days of the Symposium.

Lecture:
Human-Induced Landslides: Toward the analysis of anthropogenic changes of the slope environment. M. Jaboyedoff et al.

Orals:
Rock slope pre-failure deformation database for improved transportation corridor risk management. R.A. Kromer et al.

Characteristics and influence of brittle structures and fold geometry in the development of slope deformations in Turtle Mountain (AB, Canada). F. Humair et al.

Minor landslides and floods events affecting transportation network in Switzerland, preliminary results. J. Voumard et al.

Napoli1

Location of the Symposium.

Napoli2

During the lecture on “Human-Induced Landlisdes”.

Rockslide in Val Sterm, Graubünden

Rockslide on snow in Val Sterm (GR), Switzerland, on 15 March 2016.

At 6 PM on 15 March 2016, a 200’000 m3 rockslide occurred in the unoccupied valley Val Sterm near the village of Sedrun (GR) on 15 March 2016. Rocks fell from the East side of the North -South oriented valley and, after reaching the valley bottom, turned 90 degrees southwards and came down the snow covered valley on a runout travel distance estimated to about 1 km. Nobody were injured by the event but a water supply infrastructure was damaged.
Source: ANRSource: ANRSource: Ervin Monn Source: Ervin Monn Source: Ervin Monn Source: Ervin Monn

Large rockfall in Wolhusen

River damming by rockfall in Wohlusen (LU), Switzerland, on 11 January 2016.

At 3 AM on 11 January 2016, a 5’000 cubic meters rockfall fell from a 50 m height cliff in the village of Wolhusen in the Canton of Luzern, Switzerland. The rockfall fell into the Kleine Emme river, built a dam deflecting the river path. The cliff was described as highly hazardous in the hazard map. The neighborhood composed of residential and industrial buildings was flooded (with diesel pollution) and boulders were projected over a travel distance of 200-300 m causing damages to buildings. 20 people have to be evacuated, a main road as well as a train track had to be closed and 3 power supply installations were affected generating power failures. Nobody were injured by the event. Damage are estimated to over 1 million Swiss francs.

After the event, the cliff has been cleaned and secured. On the ground, 12’000 cubic meter of deposit material have been evacuated. Repair work including flood protection wall restoration last until early summer 2016.

Further similar rockfalls in the same site are expected and therefore the Canton of Luzern has started a global risk reduction project in this area for rockfall hazard and floods.

UAV video here (ZSO Emme).

Source: ZSO Emme

Source: Philipp Schmidli

Source: Philipp Schmidli

Source: Keystone / Urs Flüeler

Source: reader reporter

Sources: Neue Luzerner Zeitung (1), (2), (3) and (4); Neue Zürcher Zeitung (1), (2), (3) and (4).

Images from October 2016:

Wohlusen rockfall October 2016

Detail of the rockfall

Warning sign with hazard levels

Risk group @ EGU 2016 in Vienna

Twelve persons of the Risk Group participated to the European Geosciences Union (EGU) General Assembly in Vienna, Austria, on 17 April to 22 May 2016. This huge meeting brought together 13’650 scientists from 109 countries with 4’863 orals, 10’320 posters and 947 PICO presentations.

It is always an excellent opportunity for our group to meet new people and other scientists we work with during the five days of the meeting. The Risk Group people presented 30 contributions as first authors whose titles are below.

Austria Center

Jaboyedoff in PICO talk

Presentations: 2 orals and 3 PICO

  • A Multi-Scale Approach for fracture characterization. Maxime Collombin et al.
  • Automatic and global optimization of the Analogue Method for statistical downscaling of precipitation – Which parameters can be determined by Genetic Algorithms? Pascal Horton et al.
  • Rapid Offline-Online Post-Disaster Landslide Mapping Tool: A case study from Nepal. Roya Olyazadeh et al.
  • An Offline-Online Android Application for Hazard Event Mapping Using WebGIS Open Source Technologies. Roya Olyazadeh et al.
  • Impacts of the May 2015 bad weather in Western Switzerland. Jérémie Voumard et al.

Posters: 12 posters

  • A prototype web-GIS application for risk analysis of natural hazards in Switzerland. Zar Chi Aye et al.
  • Stability of Molasse: TLS for structural analysis in the valley of Gotteron-Fribourg, Switzerland. Mariam Ben Hammouda et al.
  • Specific analysis of the recent rockfall activity in the southeast face of the Piz Lischana (Engadin Valley, Graubünden, Switzerland). Susanna Büsing et al.
  • Combining SLBL routine with landslide-generated tsunami model for a quick hazard assessment tool. Martin Franz et al.
  • Intraday monitoring of granitic exfoliation sheets with LiDAR and thermal imaging (Yosemite Valley, California, USA). Antoine Guerin et al.
  • Testing failure surface prediction methods and deposit reconstruction for the landslides cluster occurring during Talas Typhoon (Japan). Michel Jaboyedoff et al.
  • Simulation of the transfer of hydrocarbons in unconfined aquifer in tropical zone: the case of benzene. Amenan Agnès Kouamé et al.
  • Analogue and numerical models coupled with structural analysis to investigate the runout of dry granular flows. Céline Longchamps et al.
  • 4 years of high-resolution LiDAR erosion monitoring of an elementary gully in the badlands of SE France (Draix). Benjamin Rudaz et al.
  • Characterization and monitoring of the Séchilienne rock slope using 3D imaging methods (Isère, France). Cindy Vulliez et al.
  • Regional transportation network blocked by snowdrifts: assessment of risk reduction strategies by the example of the wind event of February 2015 in the Canton of Vaud, Switzerland. Jérémie Voumard et al.
  • Analysis with SfM on-motion method of July 2015 extreme rainfall impacts on the S-charl valley road in the Canton of Graubünden, Switzerland. Jérémie Voumard et al.

 

 

 

Coastal cliff stability fieldwork in Normandy, France

From 20 to 24 September 2015, Clément Michoud (PhD student), Jeremie Voumard (PhD student) and Patrick Huber (Msc student) were in the area of Dieppe (Normandy, France) for LiDAR acquisitions of cliffs from a boat on the sea Channel. They used a terrestrial laser scanner coupled to an inertial unit for this survey. Although the weather conditions were not ideal, they scanned about 40 km of coastal cliff .

In addition to LiDAR data, they also took several tens of gigabytes of pictures in order to get photogrammetric models of the cliffs. Both reflex and GoPro cameras were used. When onshore, they visited landslides and rockfalls at low tide at the foot of the cliff.

This work is part of a cooperation project on coastal stability, that the Risk group has since several years with the University of Caen (Stephane Costa, Olivier Maquaire, Robert Davidson and Pauline Letortue). It was made possible thanks to a fantastic boat pilot, Alban Legardien.

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PS: Left over of Dramamine can be sent to Patrick Huber 😉