Program Technical Symposium / General Assembly 2018 in

Date: 20/21. June 2018 Location: Symposium and GA in the conference center Meet Ullevaal Stadion (Oslo) / Excursion to Kongsberg and Rjukan Language: (Euro-)English

Technical Symposium – Wednesday 20. June 2018, Brann box – MEET Ullevaal Stadion (Oslo) 8:30 Registration and welcome coffee 9:00 Welcome address Luuk Dorren (BFH) 9:10 Introduction to the technical symposium Karl Kleemayr (BFW) Session I - “Landslide and rockfall hazard analysis” 9:15 Keynote: State of the art on prediction and modeling of landslides Fausto Guzzetti (IRPI-CNR) 10:00 Shallow landslides and a changing climate in the western United States Kevin Schmidt (USGS) 10:20 Topographic model for rockfall travel distance revisited: a new method Frédéric Berger (IRSTEA) for predicting energy line angle values (results of the Alpine Space Interreg project RockTheAlps) Session II - “Geohazards in Norway and Sweden” 10:40 Landslide risk management in Sweden Yvonne Andersson-Sköld (VTI) 11:00 Next generation hazard mapping Heidi Hefre (NGI) 11:20 Introduction to geohazard problems in the region Kalle Kronholm (SKRED AS) 11:40 Historical landslides in Rjukan – introduction to the field excursion Ulrik Domaas (NGI) Lunch (12:00 – 13:30) 13:30 Regional early warning system for landslides in Norway Graziella Devoli (NVE) Session III - “Shallow landslide disposition modelling” 13:50 SlideforMap – a tool for regional landslide disposition modelling Luuk Dorren (BFH) 14:05 SOSlope – the new physically-based spring-block model for shallow Denis Cohen (COSCI) landslide disposition 14:20 Implementation of species specific root reinforcement in SOSlope Massimiliano Schwarz (BFH) 14:35 Coffee break General Assembly (GA) – all members invited 15:00 Start of the GA (the detailed program will be sent to the participants) 16:00 End of the GA

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Excursion Departure for the excursion – Wednesday 20. June 2018, Ullevaal Stadion (Oslo) 16:15 Bus departure 18:30 Arrival in the Storaas hotel, Jondalsveien 1530, 3614 Kongsberg 19:30 Evening dinner in the Storaas hotel Excursion in the Telemark region – Thursday 21. June 2018 8:15 Bus departure from the Storaas Hotel 9:15 Arrival in Rjukan 9:20 Short introduction to the history of Rjukan 9:45 The 1927 landslide and NGI Projects in Rjukan 11:45 Cable car (Krossobanen) up to the Gvepseborg Panorama Café 12:00 Lunch in the Gvepseborg Panorama Café + free time to enjoy the view 14:00 Bus departure to Drammen 16:15 Slope stability problems in quick clays (Drammen) 17:15 Bus departure from Drammen to Oslo 18:00 Arrival in Oslo

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Fifth ecorisQ General Assembly Norway, 2018 Excursion: Rjukan, municipality, Telemark County The 1927 landslide event and some NGI-projects.

NGI: Heidi Hefre & Ulrik Domaas 2 3 Krossobanen

Gaustatoppen

Norge i 3D med Norkart Virtual Globe www.norgei3d.no/ 4Geology – NGU: http://geo.ngu.no/kart/arealis 5 6 Susceptibility maps

Flooding Debris flow Rockfall NVE: https://atlas.nve.no 7

Moe Vestre Mæl Skriugata Tveitolia

Såheim Church Jordskred8 Mæl, Tinn 1983

1983.05.10 debris flow hit one house/other houses evacuated Cause: heavy rain + snowmelt New dirt road/undersized culvert – water lead along the road Uncontrolled drainage on two sites Release area: 30cm soil on top of moraine Runout area by house: 4m high debris Rjukan: 821mm/year Excavator on site/no one responsible/house destroyed 1983 event: 4% 7-10. may 60 mm (last day 32mm) Warm weather the last 4 days before event 9 Moe Vestre 20041366/20110742

Kinder garden – hazard warning P>1/1000 Debris flow deflecting dam Operated by the municipality

Ravine 10

Housing area secured with deflecting dam Cinder garten secured with hazard warning (prognosis forecast:50mm/day=closed) Debris slides in 1927 + in spring 2004: hit housing area. 7 debris slides in this area in 1927 Housing areas on debris cones 11 Tveitolia12 . Measurements of rock movements since 1975 – 1995 Catching dam/gabion Rock fall Debris slide Hazard zone hazard zone 13 Acute situation at Tveitolia 2015

2015.09.02 – acute situation: debris slide/-flow hazard 20 houses evacuated (Tveitolia) 85 mm precipitation last 24 h Cathing dam did not drain water properly 14 The 1927 landslide/debris flow event Weather report 1927: Tuddal 1896-1993 Rjukan 1884- Observed precipitation 21.06-30.06 1927 1 day 2 days 3 days 5 days 10 days Tuddal 121.0 156.1 177.9 200.0 223.1 Rjukan 134.0 148.3 178.6 201.4 213.4 Probable repeat interval for similar precipitation intencity as in 1927 1 day 2 days 3 days 5 days 10 days mm år mm år mm år mm år mm år Tuddal 121.0 300 156.1 300 177.9 230 200.0 230 223.1 90 Rjukan 134.0 700 148.3 200 178.6 230 201.4 230 213.4 65 Precipitation and intencity in Rjukan 28-29.06.1927 Dato 28.06.1927 28.06.1927 28.-29.06.1927 Time interval 08-14 14-19 19-08 mm 19.2 40.5 74.3 * Return interval: 700 year mm/hour 3.2 8.1 5.7 * High intensity the last 12-15 hours * Annual pres. 1960-1990: 834mm Saturated ground prior to the last day Last day 16% of annual pres. 15 Debris slide by the church 1927 16 Hospital/church

Rockfall hazard zone 1/1000 Debris flow hazard zone 1/1000 With unsertainty zone

Catching dam above hospital Historic Rock slide east of Hospital 17 Såheim, Rjukan 1927 18

Hazard zone debris flow

313-building now new store Ref. Einung: The immense snow masses in the mountains; snow cover until June due to a cold winter, also down the mountain sides. A sudden 19 Skriugt. warm weather changed the situation in a few hours. The debris slides in Skriugata in 1927 was released in the slopes 60-70m above the houses and not in the mountainside above. The terrain behind the houses was changed by human activity when the houses in Skriugata was built in 1914. The excavation of building sites took out the foot of the slope. It was also made a small road above that led the water away from the normal drainage path.

These human made changes increased the debris slide hazard and is part of the explanation of the incidents in Skriugata in 1927. Methods 20 Vemork, Rjukan, municipality of Tinn. Lidar scan = efficient method – volume and stability Transport of heavy equipment. Upgrading the Vemork Power plant, Rjukan, 2010.

Loose Prelease rock fracture surface

Consequenses Risk

Optech ILRIS-3D laser skanner Differential GPS. LiDAR data: 28 000 m3 21 22 23 24 Historic events: Vemork railway/road 1927-2010: 30 rockfalls on the «Vemorkbanen» railway, now road 4 debris slides Historic events (Hydro Energy, Newspaper) Expect 2 events per year

1927 25 Geohazards in Norway: Quick clay slides

•Last 100 years mainly released by human activity •River and stream erosion is important •Rare, large events with potentially large consequences.

•150 fatalities last 150 years Recent26 quick clay slides, with large consequences!

Sørum (2016)

Lyngseidet (2010) Skjeggestad (2015) 27

Rissa, Trøndelag, 1978 28

From left: - Schematic picture of clay sedimented in fresh water (a) and in salt water (b), (after Pusch, 1970. Fra SGI - "Kvicklera – bildning och egenskaper – litteraturstudie". Karin Rankka, 2003) / A picture series of quick clay: loading, remoulded clay, adding table salt, and firm clay after mixing the salt into the clay pore water. 29 Risk evaluations of quick clay slides in Norway 30 31 32

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