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Université de Fribourg

Monitoring of high alpine mass movements combining laser scanning with digital airborne photogrammetry

Kenner, R. ; Bühler, Y. ; Delaloye, Reynald ; Ginzler, C. ; Phillips, M.

In: Geomorphology, 2014, vol. 206, p. 492–504

Airborne- and terrestrial laser scanning are used in combination with digital airborne photogrammetry to monitor surface changes between 2009 and 2011 on rock glaciers and landslides at three mountain permafrost sites (Grabengufer, Schafberg and Flüela Pass) in the Swiss Alps. 3D surface changes detected through comparison of multitemporal laser scanning data, as well as horizontal creep rates...

Université de Fribourg

Landslide mapping in Switzerland with ENVISAT ASAR

Wegmuller, Urs ; Strozzi, Tazio ; Delaloye, Reynald ; Raetzo, Hugo

In: Geoscience and Remote Sensing Symposium (IGARSS), 2012, p. -

In the frame of the IGARSS 2012 special session on ENVISAT the landslide mapping activities in Switzerland using ENVISAT ASAR data are presented. Between 2005 and 2010 the building up of a well suited archive over the Swiss Alps was realized through programming of all IS2 mode data during the snow free period. In recent years DINSAR and PSI based landslide inventory and monitoring products...

Université de Fribourg

Surface subsidence and uplift above a headrace tunnel in metamorphic basement rocks of the Swiss Alps as detected by satellite SAR interferometry

Strozzi, Tazio ; Delaloye, Reynald ; Poffet, Damien ; Hansmann, Jürgen ; Loew, Simon

In: Remote Sensing of Environment, 2011, p. -

Surface subsidence associated with the construction of a headrace tunnel in the Swiss Alps at more than 2000 m above sea level (a.s.l.) has been detected at two locations with satellite differential Synthetic Aperture Radar (SAR) interferometry. At the first location, a subsidence trough of about 4 cm in the satellite line-of-sight direction following the headrace tunnel axes has been measured...

Université de Fribourg

Rapid changes of the ice mass configuration in the dynamic Diablotins ice cave – Fribourg Prealps, Switzerland

Morard, Sébastien ; Bochud, M. ; Delaloye, Reynald

In: The Cryosphere, 2011, vol. 4, p. 489-500

The Gouffre des Diablotins is a deep cave system located in the Swiss Prealps. In 1991, the lower entrance zone of the cave was almost free of ice. Nevertheless the ice volume sharply increased in 1994, plugging almost totally the gallery from the lower entrance. The ice cave has also experienced a flood period between 1996 and 2007 and very heterogeneous ice surface morphologies and textures...

Université de Fribourg

Combined observations of rock mass movements using satellite SAR interferometry, differential GPS, airborne digital photogrammetry, and airborne photography interpretation

Strozzi, Tazio ; Delaloye, Reynald ; Kääb, Andreas ; Ambrosi, Christian ; Perruchoud, Eric ; Wegmüller, Urs

In: Journal of Geophysical Research, 2010, p. F01014

Recent global warming, through the related retreat of mountain glaciers, causes a growing number of different slope instabilities requiring accurate and cost-effective monitoring. We investigate the potential of combined remote sensing observations from satellite and airborne microwave and optical sensors for an efficient survey of mountainous ground displacements. The evolution of a paraglacial...

Université de Fribourg

Contribution à l'étude du pergélisol de montagne en zone marginale

Delaloye, Reynald ; Monbaron, Michel (Dir.)

Thèse de doctorat : Université de Fribourg, 2004 ; no 1441.

L’objectif principal de cette thèse est l’identification de processus régulant la présence et l’évolution du pergélisol dans les zones marginales de son domaine d’existence, c’est-à-dire là où sa présence est fortement discontinue, sporadique, voire incertaine. Cette thématique n’a que peu été étudiée jusqu’à ce jour. Cependant, comme les interrogations portant sur...

Université de Fribourg

Analyzing rockfall activity (1600–2002) in a protection forest—a case study using dendrogeomorphology

Stoffel, Markus ; Schneuwly, Dominique M. ; Bollschweiler, Michelle ; Lièvre, Igor ; Delaloye, Reynald ; Myint, Moe ; Monbaron, Michel

In: Geomorphology, 2005, vol. 68(3-4), p. 224

For the first time, dendrogeomorphology has been used to investigate spatial and temporal variations of rockfall activity in a protection forest. We report results of 564 cores from 135 severely injured Larix decidua Mill. trees on the west-facing Täschgufer slope, Swiss Alps. While trees sampled reached an age of 297 years on average, the oldest one attained breast height in AD 1318. For...

Université de Fribourg

Evidences of winter ascending air circulation throughout talus slopes and rock glaciers situated in the lower belt of alpine discontinuous permafrost (Swiss Alps)

Delaloye, Reynald ; Lambiel, Christophe

In: Norwegian Journal of Geography

The winter ascending circulation of air throughout an accumulation of coarse slope sediments (the so-called chimney effect) facilitates the cooling of the ground and even the occurrence of permafrost in the lower part of a deposit. Simultaneously, any freezing is unlikely to occur in the upper part. The chimney effect has been reported to date mainly for cold and sometimes perennially frozen...