Swiss History

• suffered several large landslides – Elm (1881; 155 deaths) – Goldau (1806; 457 deaths) – Flims , Sierre… Situation, Geology and • Foundations for landslide sciences through the work of Heim geomorphology of Les (1932) (Eisbacher and Clague, 1984). • In 2006, the bicentenary disaster of Goldau was officially region commemorated with an interesting scientific meeting • Catas trophes can be considered as the cement of the Swiss M. Jaboyedoff, Choffet M., Loye A., Michoud C., Oppikofer T., PedrazziniA. nation, because of the mutual assistance between Swiss regions (Pfister, 2002) Risk - g ro up - IST - Institute o f Ea rth Sciences • As in many European countries, the problem of the overexploitation of forests in Switzerland increased landslides, floods and snow avalanches hazards within the Alpine territory – Forest protection law in 1876, which can be considered as one of the first laws integrating natural risk management and risk reduction strategies (FOEN, 2001).

08.04,2014 CHANGES - INTENSIVE COURSE 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Switzerland Global Warming in Switzerland

• World global warming was around 0.6° C for the 20th • Population 7.5 million; Area 42’000 km2 century • Population density •In Switzerland – Average 183 inhabitants/km2 – Up to 1.6°C in western Switzerland – 305 inhabitants/km2 when excluding the mountainous regions –1.3°C in Swiss German part and – 594 inhabitants/km2 in some urbanized cantons –1°C in the south Swiss Alpine region (OcCC, 2007). • 6% of the Swiss territory is affected by landslides Expenses • In the past the followed a more rapid warming than for natural hazard in Switzerland other regions (IPCC, 2001). –0.6% of GDP (gross domestic product) or 2 billion USD – Alps, like other cold regions, are more sensitive to climate •4.7% of the Federal state change. • 3.7% of the Cantonal (=regional authorities) – Permafrost thawing or glacier retreat make the Alps more • 5.7% of the municipal budgets – 750 million USD are dedicated to risk prevention hazardous than other regions. – 300 million USD are used for emergency actions. • The increase in extreme events (O cCC, 2007), especially intense precipitation events (OFS, 2005; Noverraz & Bonnard 1990; Lateltin, 1997; FOEN, 2007)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

1 “Hazard” maps in Switzerland How to reach Kyoto in fro Switzerland: Sequester CO2 yes but how? Mapped surfaces by phenomena • In Switzerland the increase of the forest will play that role temporarily (from FO EN, 2006) (the equivalent CO 2 emissions is approximately 50 million tonnes per year for Switzerland.

Mapped surfaces within cantons Flood hazard mapping progress Snow avalanches Floods RockfallsLandslides ( -ha rd ro c k ins ta b . ) Hazard maps in Switzerland: a 2 stages process: • Not comp leted – Reg ion al scale: indicative dan ger • Partially completed map • In progress – Danger map: only in at risk area • Ended Landslide hazard mapping must be • Ended and included in completed in 2011. landplaning programme From Environment magazine 02/07

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Mudflow in Les Diablerets Shallow landslides an emerging problem

• One mudflow, of approximately 500 m3, cut a small mountain road located at 1750 m a.s.l. close to tree line altitude. • The area contains several small shallow landslide scars within moraines and colluviums. • Most of them are related to track cuts. • Affected grey and brownish moraine –The moraine is weathered and that the pore pressure can be affected by such a modification. – Presence of a water pipe • The triggering factor was heavy rainfall, which was not exceptional (probably a return period of less than 3 years).

• A) Sh allow land slid e scar. (B) Front of th e mu d slid e sh owin g a large b lock th at can h ave a large d estru ctive impact. (C) Pictures showing the pipe and its defect. (D) Limit between what is expected to be the contact b et ween weat h er ed mor ain e ( b r own ish ) an d t h e u n weat h er ed mor ain e ( gr ey) ( mod ified fr om B on r ip osi et al, 2007).

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

2 Debris slide of Pont Bourquin (les Diableret s) - July 5, 2007 Introduction à la géologie Alpine • Triggered by heavy rainfall • The material was part of a larger shallow landslide of around 40'000 m3, which belong itself to larger landslide affecting the entire slope. • The movement initiated around 2004 • Preparation by erosion producing approximately 3000 to 6000 m3 of debris that were accumulated down slope. •The forest is becoming old, without maintenance, and has grown on former pasture, indicated by farms ruins. •Some chalets are now renovated for tourism and running water is often installed.

General view of the Alps Google Earth

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Municipality of Oromonts-Dessus

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

3 Les Diablerets (municipality of Ormont- Dessus) •Ormont-Dessus – Altitude 1'128 m – Area 61.5 km2 – Population in 2008 1'417 (+29) – Debt 7’007.- CHF/inhab.

Employem ent per sec tor s Employeme nt rate Number Percent Number Pr im ary sec tor 49 10 % > 90% 32 Se condary se ctor 91 18 % > 50% 16 Ter tia ry sector 355 72 % < 50% 30 495 78

From http://www.scris.vd.ch/ and http://www.bfs.admin.ch

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Evolution of the work positions and A few statistics (2000) exportations in agriculture Territory Altitude of the center 1128 m

Total Surface area 61.5km2 Fo re st 31 % Farming 33 % Habi tat i nfrastructures 3 % Unprod uctive area 32 % Population evolution Working outside the municipality

From Stïcki and Rognon, (1998) From http://www.scris.vd.ch/ and http://www.bfs.admin.ch

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

4 From 1980 to 1992: •the forested areas increased by 3.8% . But the way to estimate this surface changes since that time •Infrastructure increased by 14.5%

Geology of western Alps (from From Stïcki and Rognon, (1998) Escher et al., 1997).

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Corss-sect ion of t he A lps (Escher et al., 1997)

Te c t o n i c M a p of the Alps romandes

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

5 Major palaeogeographic alpine areas during the Cretaceous period, according to Marthaler 2001

Model uplift of the Alps , ac cording to Escher and Beaumont (1997)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

57 960 0 5 800 00 58 040 0 .000000 .000000 .000000 . 000000 . 000000 133 600 133 600 00 00 . 0000 . 0000 133300 ® 133300 050 100 200 300 400 Meters

57 960 0.000000 5 800 00.000000 58 040 0.000000 Tectonics (from Badoux and Gabus, 1990) Tectonics (from Badoux and Gabus, 1990) 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

6 Geological Cross-section (f rom Badoux and Glacier maximum at Würm af t er Jäckli Gabus, 1990) (1962)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

View of Les Diablerets area (data from Glacier maximum at Würm af t er Jäckli swisst opo) (1962) in les Diableret s

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

7 Map of glacier in the Ormont valley bef ore 10’000, wit h no link wit h Rhone Rhodanien elements The glacier of Rhône was probably higher than 1600 m, permitting the Rhône ice entering within the Grande- eau valley.

From S ch oen eich (19 98)

From S ch oen eich (19 98)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Analysis near les Diablerets village Retreat moraine of the Dar glacier

Unite 1 fluvioglacial deposits from the Dar Glacier and moraine from Grande eau Glacier (unite 2) From S ch oen eich (19 98) From S ch oen eich (19 98)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

8 Origin of rock elements in the moraines Location of the latest stages of retreats

From Schoeneich (1998)

From S ch oen eich (19 98) 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Glacial stage near les Diablerets Glacier stages near

From Schoeneich (1998) From S ch oen eich (19 98)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

9 Dates obtain by C14 on wood (From Schoeneich, 1996) Fast retreat in Two landslides are les Daiblerets developed near area les Diablerets:

1. Les Parchets since approx. 2000 years 2.Les Belvédère since more 5000 years

From Schoeneich (1998)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

La Frasse landslide

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

10 AUSCULTATION DES MOUVEMENTS DES GLISSEMENTS DE UTILISATION DE LA TERRAIN ET DES EBOULEMENTS PHOTOGRAMMETRIE (Tiré de slides de C. Bonnard) (Tiré de slides de C. Bonnard) I ntr oduction Méthodes topographiques Evaluation des vitesses moyennes annuelles Méthodes photogrammétriques de déplacement horizontal au glissement de Monthly rainfall 600 La Frasse, grâce à 5 jeux de photos aériennes Utilisation des anciens plans 18m mm : cadastraux Mesure continue des mouvements - Jaune : période 1957 – 1969 Déplacements en profondeur - Vert : période 1969 – 1974 Autres systèmes -Bleu : période 1974 – 1980 -Rouge : période 1980 – 1982 Mesures piézométriques Cellules de charge et de pression de La variabilité tant spatiale que temporelle est terre forte sur l‘ensemble du glissement Evolution des mouvements au Implantation possible des glissement de La Frasse, instruments pendant 30 ans, comparée à la Conclusions pluviométrie

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

CAMPARAISON D’ANCIENS PLANS CADASTRAUX (Tiré de slides de C. Bonnard) Location of the landslide of La Frasse

•

Applic ation au glis s ement de La Frasse

Les documents datent de 1768 et 1861. Les bornes ont été remesurées en 1980. Les vitesses à Cergniat sont de l’ordre de 13 cm/an

• Average s urfac e veloc ities are indic ated (modified from http://www.geopla net.vd.c h/) : from Noverraz and Bonnard,1988)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

11 View (Data swisstopo) La F rasse et le SLBL

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

EXEMPLE DE PROJET DE DRAINAGE AU DInSAR – on La Frasse GLISSEMENT DE LA FRA SSE (VD) Data GSAR® VARIANTE ACTUELLE : 16 Forages verticaux munis de pompes, (from T. Rune uniquement sur la zone aval la plus active Lauknes; (fonctionne depuis plus de 10 ans). Les Norut, Tromsø, déplacements mesurés actuellement sont faibles (< 10cm/an) Norway)

VARIANTE PROPOSEE : Galerie de drainage de 720m de longueur, à Equivalent to partir de laquelle seront forés des drains rayonnants de 30 à 50m de long. Le crédit a été PS-INSAR but voté à fin 2006 par le Grand Conseil. on areas…

La modélisation des mouvements avec et sans drainage montre que le drainage réduit de 95% Results les déplacements lors d’une crise compatible with (Tiré de slides de C. Bonnard) terrestrial

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M.measurements Jaboyedoff et al.

12 Average temperature the earth surf ace the La Frasse Landslide age eart h during t he last 10’000 years Probably around 9000 years ago

The glacial erosion plays probably a great role

From Stücki and Rognon, (1998) From S ch oen ei ch ( 19 98; after Gabu s, 198 2))

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Landslides “hazard map” in les Diablerets Location of the Pont Bourquin landslide areas (from www.geoplanet.vd.ch)

Base from Swisstopo

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

13 Geometrical characteristics of Bourquin Debris slide of Pont Bourquin (les landslide Diableret s) - July 5, 2007

•Length = 244m • A rea = 8220 m2 •Width

–Wmin = 35 m

–Wmean = 35 m

–Wmax = 60 m

Base from Swisstopo • Front of the debris slide that was partly cleared from the road

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Debris slide of Pont Bourquin (les Debris slide of Pont Bourquin (les Diableret s) - July 5, 2007 Diableret s) - July 5, 2007 • Triggered by heavy rainfall • The material was part of a larger shallow landslide of around 40'000 m3, which belong itself to larger landslide affecting the entire slope. • The movement initiated around 2004 • Preparation by erosion producing approximately 3000 to 6000 m3 of debris that were accumulated down slope. •The forest is becoming old, without maintenance, and has grown on former pasture, indicated by farms ruins. •Some chalets are now renovated for tourism and running water is often installed.

• Cross-section along the major slide indicating the debris

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

14 Landslide activity

• Part of a former landslide, at the west of a former scar • Orthophotos of the upper part of the landslide during the last 13 years. Observe the increase in size of the erosion area especially between 1997 and 2004. Some ortho-rectification problems exist between the photos (data from SWISSIMAGE © 2008 swisstopo (DV012716)).

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Geological setting after event and new Geological setting investigations

• 4 geological units within 300 m of landslide • Delimited by important tectonic thrusts dipping toward North within 20° to 30° • The bedding which allows flexural toppling within the first meters • “Deep Landslide” Volume = ~40’000 m3

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

15 A zone of landsliding Debris-flow in Pont Bourquin

Landslides inventory indicate that the zone was affected by slow movements < 2 cm/year

(from http://www.geoplanet.vd.ch/elnat/index.html). 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

View of the top of Pont Bourquin Landslide Schists alteration

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

16 View of the event cutting the road View of the f ront of the landslide mass

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Pont Bourquin area Pont Bourquin area

From Eggertzwiller (in prep.) From Eggertzwiller (in prep.)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

17 Pont Bourquin area Pont Bourquin area

Base from Swisstopo

From Eggertzwiller (in prep.) From Eggertzwiller (in prep.)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Floods

Base from Swisstopo

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

18 Le Matin, 26 juin 2005

Le Matin, 26 juin 2005

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Hoteldes Source (http://www.rts.ch/info/suisse/1097327‐inondtion‐les‐ diablerets ‐vd‐evitent‐le‐pire.html)

http://www.24heures.ch/vaud‐regions/ riv iera‐chablais/diablrets‐coup‐ grosse‐inondation/story/23906679 P h oto: R. Metzg er 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

19 P h oto: R. Metzg er P h oto: R. Metzg er 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

P h oto: R. Metzg er P h oto: R. Metzg er 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

20 P h oto: R. Metzg er P h oto: R. Metzg er 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Mitigation at La Frasse

Base from Swisstopo

Mu sée d es Ormon t

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

21 Hazard map of flooding along the Grande eau and Dar Diablerets (source: B + C) Snow avalanches

• Photo d’une des avalanches de 1984 (Tiré de Stucki et Rognon, 1998 ; Photo J.

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014Francey).. CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Danger map of snow avalanches in les Diablerets areas (from www.geoplanet.vd.ch)

Interaction between natural hazard and human activity

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

22 Indicat ive maps of dangers f or debris- Indicat ive maps of dangers f or rockf all f lows and mudf lows

.000000 .000000 .000000 .000000 .000000 .000000 .000000

575000 57 6000 577 000 57800 0 579000 580000 58 1000 0 .000000 .000000 .000000 .000000 .000000 .000000 .000000 0000 000 5750000 57600 0 577 000 57 8000 579000 58000 0 5810 00 0 .00 .00 0000 0000 .0 .0 136800 136800 13 6800 13 6800 0000 0000 0 0 μ μ . 00 . 00 0000 0000 .0 .0 13590 0 13590 0 13 5900 13 5900 000 000 00 00 . 000 . 000 . 0000 . 0000 1350 00 1350 00 1350 00 1350 00 00 00 . 0000 . 0000 000 000 . 000 . 000 1341 00 1341 00 13410 0 13410 0 00 00 . 0000 . 0000 0000 0000 . 00 . 00 13 3200 13 3200 133200 133200

Meters Base from Swisstopo Meters Base from Swisstopo 025 0 500 1'000 1'500 2'000 025 0 500 1' 000 1' 50 0 2' 00 0

575000 .000000 57 6000.000000 577 000.000000 57800 0.000000 579000 .000000 580000 .000000 58 1000.000000

575000 .000000 57600 0.000000 577 000.000000 57 8000.000000 579000 .000000 58000 0.000000 5810 00.000000 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Indicat ive maps of dangers f or landslides Situation in 1961

575 000.000000 57 6000.000000 5 77000.000000 57800 0.000000 5790 00.000000 58 0000.000000 5 81000.000000 00 00 000 000 .0 .0 1368 00 1368 00

0 μ 0 0000 0000 .0 .0 135 900 135 900 0 00000 0000 .0 .0 13 5000 13 5000 0 00000 0000 .0 .0 13 4100 13 4100 0 0000 000 .00 .00 13 3200 13 3200 Base from Swisstopo Base from Swisstopo Me ters 025 0 5 00 1' 00 0 1' 50 0 2 '0 00

08.04,2014575 000.000000 57 6000.000000 CHANGES5 77000 - INTENSIVE.000000 COURSE57800 0.00 Les0000 Diablerets 57902014 00.0000 –00 M. Jaboyedoff58 0000et .0al.00000 5 81000.000000 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

23 Situation in 2006 Risk management by moving chalet s

Since 1950 chalets located on la Frasse have been moved

(From Schoeneich and Busset-Henchoz, 1998)

Base from Swisstopo

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Houses build t o support snow Proportion of houses at risk per year of avalanches called a case “une case” building of houses

100.0

90.0

80.0

70.0

60.0

50.0 Dangers %

40.0

30.0

20.0

10.0

0.0 The house is slightly buried and built in with stones 1961 1969 1974 1980 1992 2000 2006 Ye ar s of ho us es b ukd in gs (From Schoeneich et al., 2002) From Morel and Sandri (2008)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

24 Proportion of houses at risk per year Recent houses are built on landslides

75 .0

70 .0

65 .0 % Dang ers 60 .0

55 .0

50 .0 19 61 196 9 1974 1 980 199 2 2000 2 006 From Morel and Sandri (2008) Y ear s From Morel and Sandri (2008)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al.

Comparison of Buildings density from 1961 and Density of buildings by km2 (after F. 2006 and direction number from the center Eggerzwyler)

N ombreNombre de maide mais onss ons sel onsel onla di larec direc ti on tionen en196 200 1 0 N 0° 350N 0° 350 300 300 NW 315° 250 NE 45° NW 315° 250 NE 4 5 ° 200 200 150 150 100 100 50 50 W 270° 0 E 90° W 270° 0 E 90°

SW225° SE 135° SW225° SE 135°

S 180° S180°

Den sité de bâtim ents en 2004 [ nb/km 2]

pr o file d04 < VALUE> 0 0 - 25

25 - 5 0 50 - 1 00 10 0 - 25 0 25 0 - 50 0 50 0 - 85 0 From Morel and Sandri (2008)

08.04,2014 CHANGES - INTENSIVE COURSE Les Diablerets 2014 – M. Jaboyedoff et al. 20-21 sept. 2012 Cours hors campus Master environnement - les Diablerets –M. Jaboyedoff et al.

25 Cross-section of the density of buildings by km2 (af t er F. Eggerzwyler)

Densité de b âtiments par km2

800

700

600 1942 1974 500 1992 2004 400 Densit é 300

200

100

0 - 1'000 2'000 3'000 4'000 5'000 6'000 Dst ance [m]

20-21 sept. 2012 Cours hors campus Master environnementfrom: - les Diableretswww.geoplanet.vd.ch/ –M. Jaboyedoff et al. 20-21 sept. 2012 Cours hors campus Master environnement - les Diablerets –M. Jaboyedoff et al.

Normalized cross-section of the density of Spreading of houses (phot o from buildings by km2 (af t er F. Eggerzwyler) Museum Ormont s 2008)

D ensité d e bâtimen ts par k m2 Normée au maximum

1.0 0

0.9 0

0.8 0 19 42 0.7 0 19 74 0.6 0 19 92 20 04 0.5 0 De nsité 0.4 0

0.3 0

0.2 0

0.1 0

0.0 0 - 1' 00 0 2 ' 00 0 3' 0 00 4' 0 00 5' 0 00 6' 0 00 Dstance [m]

20-21 sept. 2012 Cours hors campus Master environnement - les Diablerets –M. Jaboyedoff et al. 20-21 sept. 2012 Cours hors campus Master environnement - les Diablerets –M. Jaboyedoff et al.

26 Conclusions

• Les Diablerets area landsliding activity started after the retreat of the local glaciers – The outcropping rocks are the mains causes, but in some cases the glacial erosion promoted landslide location • Glacial deposits can be involved in the mass movements • The risk for flood and landslides was managed in the les Diablerets area • But the extension of the village take only partially in to account the hazard such as floods and landslides

20-21 sept. 2012 Cours hors campus Master environnement - les Diablerets –M. Jaboyedoff et al.

27