All posts by Marc-Henri Derron

Scientific stay of Teresa Gracchi in the group RISK

Teresa Gracchi will stay for 6 months in the group RISK at UNIL. Teresa is a joint-PhD student at the Department of Civil and Environmental Engineering of the University of Florence and at the Faculté des Géosciences et de l’environnement of the University of Lausanne, in the framework of the International Doctorate in Civil and Environmental Engineering program. Her research involves the use of innovative techniques for landslide monitoring, such as wireless sensor networks. In particular, she deals with a low-cost and easy to install system suitable for emergency monitoring, based on ultra-wideband technology. During her stay at UNIL, she will focus in viewshed analysis from LIDAR point cloud, to develop a tool that allows finding the best positions to install a wireless sensor network.

Welcome Teresa and we wish you the best for your project

4th Slope Tectonics Conference – Kyoto Oct. 2017

The 4th Slope Tectonics Conference was held from 14 to 18 October 2017 in Japan. It started with two days of presentations at the University of Kyoto and was followed by three days of fieldtrip in the Kii penninsula. As a reminder, the Slope Tectonics Conferences were initiated in Lausanne in 2008 (and then in Vienna in 2011 and Trondheim in 2014).

Michel Jaboyedoff and Marc-Henri Derron took part to this conference with two oral presentations:
3D failure surface and volume estimation of large rock slope instabilities: a review of a bottleneck problem
Slope deformation imaging of sandbox analogue models (LiDAR and InSAR)

Fieldcamp in Barcelonnette 2017

Beginning of June 2017, the field-camp in risk and slope processes for master students took place in the valley of Ubaye, at Barcelonnette (France). During almost two weeks, the students have mapped the Lavalette landslide, analysed the stability of a large rock wall, made rockfall mapping and numerical modelling, and discovered the debris flows mitigation measures in the Riou Bourdou watershed.

This camp was made possible thanks to the center Seolane and the kindness of Georges Guiter from RTM:

New comers in the RISK group

A couple of people arrived recently in the group. Cecile d’Almeida, from the University of Grenoble, will spend 5 months with us to do her master thesis on rockfall analysis (LiDAR, …). Caroline Lefeuvre, who achieved some months ago her master (within the RISK group but for the Ecole des Mines de Alès), has been hired until next summer to continue the research she started on the thermal behavior of rock slope. Finally Francois Noel, from the University of Laval (Québec) has started a PhD thesis on rockfall, with a strong focus on true 3D modelling of propagation.

3D propagation modelling by Francois Noel

VGC 2016 – Bergen, 21-23 September 2016

The second Virtual Geoscience Conference was held in September in Bergen (Norway). Organized by CIPR and the University of Begren, over 100 persons took part to this multidisciplinary conference which aims at understanding the recent trends and convergences of research in geomatics (spatial science), 3D visualisation, computer graphics, as well as virtual and augmented reality into geosciences applications. A large panel of scientist from geohazards, geology, geomorphology, reservoir engineering, surveying, 3D computing as well as infrastructure and natural resources were present. vgc16a

The Risk group of UNIL contributed to several presentations during VGC2016:

  • Exfoliation sheets detection with terrestrial laser scanning and thermal imaging (Yosemite Valley, California, USA). A Guerin, M-H Derron, M Jaboyedoff, A Abellán, O Dubas, BD Collins & GM. Stock.
  • Development of a TLS real-time monitoring system for landslides. RA Kromer, A Abellan, J Hutchinson, M Lato, M-A Chanut & M Jaboyedoff.
  • Point cloud time series for monitoring landslide processes: Displacement field analysis using image correlation and optical flow algorithms. P Bornemann, A Guérin, J-P Malet, C Vulliez, J Travelletti, A Puissant, M-H Derron, M Jaboyedoff, M-A Chanut & L Dubois.
  • Rockfall monitoring of a poorly consolidated marly sandstone cliff by TLS and IR thermography. C Lefeuvre, A Guérin, D Carrea, M-H Derron & M Jaboyedoff.
  • Virtual analogues of Ypresian carbonated fractured reservoir at Ousselat Cliff (Central Tunisia) using terrestrial laser scanning and GigaPan techniques. R Mastouri, A Guerin, M Jaboyedoff, S Bouaziz, M-H Derron, M Lazzez & A Boulares.

The full proceedings volume of VGC2016 is available at:

The VCG cycle (initially Vertical Geology Conference) was initiated in Lausanne in 2014. The third conference will take place in Kingston Canada.vgc16b

Barcelonnette 2016 field-camp

Beginning of June and for the third time, the field-camp for master students took place in the Ubaye Valley, in the area of Barcelonnette (France). 15 students had the opportunity to observe, map and analyze the landslide of La Valette and Super Sauze, the debris flows of Riou Bourdou, and the rockfalls of Le Cop.

This 11 days field trip was made possible thanks to the facilities of the center Seolane at Barcelonnette.

Participants on a wood check dam in the area of Riou Bourdou

Fractures surveying at Le Cop cliff

Evening work at Seolane

Molasse stability at Fribourg

Stabilité des parois de molasse dans la région de Fribourg
Since March 2015, a new project has started with the Canton of Fribourg dealing with cliffs collapse in marine molasses. Mariam Ben Hammouda, PhD student from the Risk-Group, is working in collaboration with Benoît Mazotti, scientific collaborator of the Natural Hazards section in Forest Service and Wildlife (SFF) of Fribourg.
Because of some recent rockfalls, 4 sites were selected to survey the stability of molasse cliffs and to study the triggering factor.
In that purpose GigaPan acquisition were done for two sites and Lidar scanning for all of them (
This project aims to assess the susceptibility to rupture of cliffs in molasses and it will be involved as a case study in Mariam’s PhD.

Gottéron Madeleine

Left: a site in the Gotteron valley (with the LiDAR device). Right: site of La Madelaine (with the Gigapan device).

Two PhD students at the Laram School 2015 – China

LARAM School (LAndslide Risk Assessment and Mitigation)-2015
3rd Asia Course 14 – 25th September 2015, Chengdu (China)
滑坡灾害风险评价与管理” 际博士课程 2015

LARAM is an International School on “LAndslide Risk Assessment and Mitigation” of the University of Salerno. The School is held annually, and took place for the 3rd time in Chengdu (China) in 2015. It gathers every year 40 PhD students with Civil, Environmental or Geological Engineering backgrounds.

Mariam Ben Hammouda, a PhD student from the Risk group, and Ryan Kromer, a PhD visitor from Queen’s University in Canada, could join this summer course. The main objective of the School is to develop high educational interdisciplinary programs for assessing, forecasting and mitigating landslide risk.


Laram School:

Two Italian PhD students visiting the group

This month two PhD students arrived from Italy for visiting the Risk group

Lucia Losasso is PhD student at the Engineering School of the University of Basilicata (Southern Italy). Her course in Engineering for Innovation and Sustainable Development address the study of innovative models for landslides risk assessment along roads in complex geomorphology areas (supervisor: Francesco Sdao). Lucia will stay at Unil until March 2016 to improve her knowledge in landslides susceptibility and risk assessment using different original models and softwares of the Risk Analysis Group.

Valerio Sorrentino is PhD student of “Earth, Environmental and Resources Science” from the University of Naples “Federico II”. He will stay in Lausanne for two months to work on his research project about “rockfall susceptibility in the Cilento carbonatic cliffs, Campania region” ( supervisors: Paola Romano & Antonio Santo). In Lausanne, Valerio will develop his knowledge and practical skills in 3D point clouds processing.

Welcome to both of them !


Cilento carbonatic cliffs, Campania, Italy (picture: Valerio Sorrentino)

The Risk group in the national French TV news

Le groupe Risk de l’UNIL au 20 heures de France2

On Tuesday 3rd November 2015, three minutes of the TV news of the French national channel France2 were dedicated to research activities that Ludovic Ravanel (CNRS, University of Savoie) and the Risk Group (ISTE, University of Lausanne) have together in the Mont-Blanc massif. This research takes place around the Drus Mountain, an iconic peak of the Chamonix valley. The 1000m high West face of the Drus is affected by intense rockfalls since the beginning of last century. In June 2005, a large event of 265’000 m3 (Ravanel and Deline, 2009) destroyed the Bonatti pillar and numerous legendary climbing routes. Since 2010, the Risk Group proceeds to laser scanning acquisitions (LiDAR) every year in late season. These data are used to build high resolution 3D models of the relief, to estimate volumes of rockfall events and to analyze the mechanisms involved (Matasci et al., in prep).
On 2nd November 2015, two reporters of France 2 accompanied Ludovic Ravanel (CNRS, University of Savoie), Antoine Guérin and Susanna Büssing (both from UNIL) for one day work in the field. Their TV report was broadcasted the following day in the main TV news of France2:,130396764.html
(from 28’20” to 31’40”)