Field trip

Thursday 13 Sept. 2018 afternoon (1:30PM-7PM)

=> Gala dinner is full. Thank you to not register anymore.

Warning: Coming back at Grenoble around 7PM - Do not plan to fly back on Thursday evening.

This field trip will lead us in the Trièves area, a wide and beautiful depression filled with alternations of Quaternary clays and silts deposited in a glacially-dammed lake during the Last Glacial Maximum. After the retreat of the glacier, around 20 000 years ago, rivers started to incise the soft clayey sediments and initiated landsliding in the whole area. The most-active of these landslides is known as the “Harmalière landslide”. It affects an area of around 18 106 m². This landslide suffered several reactivation phases. The last one occurred in 2016-2017, and generated impressive sub-vertical headscarps and a consequent flow. This last reactivation led the Grenoble Observatory (OSUG) together with the French Observatory on Gravitational Instability (OMIV) to monitor different physical parameters from space and from in-situ instrumentation (GPS, seismometers, piezometers). The field trip will be conducted by landslide specialists to visit the installations.

> Objectives: deglaciation / glaciation in the Alps and associated active deformation

• Visit of the instrumented active landslide of Harmalière in the Triève (an instrumented site from the OSUG Observator).
• Measurement techniques.
• Contribution of the geodesy (in the broad sense: GPS + sat) for the problematic movements of ground.

> Previsionnal timetable:

• 1h30PM: Departure after lunch from CRAYA Amphitheatre by bus
• 3PM - 5:45PM: Visit of the active landslide
• Coming back at Grenoble around 7PM

> Nb of participants max: 50

> Price: 18€ in addition of registration fees

> Necessary equipment:

• Walking shoes
• Sweater
• Raincoat / umbrella
• Change

> Guides: Gregory Bièvre and Jérôme Nomade

> References: 

• Bièvre, G., Jongmans, D., Winiarski, T., Zumbo, V., 2012. Application of geophysical measurements for assessing the role of fissures in water infiltration within a clay landslide (Trièves area, French Alps). Hydrol. Process. 26 (14), 2128–2142.
• Jongmans, D., Bièvre, G., Schwartz, S., Renalier, F., Beaurez, N., 2009. Geophysical investigation of the large avignonet landslide in glaciolacustrine clays in the Trièves area (French Alps). Eng. Geol. 109, 45–56.
• Lacroix P., G. Bievre, E. Pathier, U. Kniess, D. Jongmans (2018), Use of Sentinel-2 images for the detection of precursory motions before landslide failures, Remote Sensing of Environment, in press.
• Renalier, F., Jongmans, D., Campillo, M., Bard, P.Y., 2010a. Shear wave velocity imaging of the Avignonet landslide (France) using ambient noise cross-correlation. J. Geophys. Res. 115, F03032.