Embed Size (px)
DESCRIPTION
The research project: objectives and organization. PERMAdataROC. ‘‘Development of a database and monitoring methods for slope instabilities and rock temperatures in steep alpine rockwalls affected by permafrost ’’. INTERREG IIIA France/Italy Project # 196 (03/2006 – 03/2008). - PowerPoint PPT Presentation
Citation preview
The relation of permafrost degradation and slope instabilities in The relation of permafrost degradation and slope instabilities in high alpine steep rockwalls: the research project PERMAdataROChigh alpine steep rockwalls: the research project PERMAdataROC
Recently, large rock and rock/ice avalanches have occurred in high mountain areas worldwide (Mc Ginnis Peak, Alaska, 2002; Kolka-Karmadon, Caucasus, 2002). In the Alps, Brenva Glacier (1997), Matterhorn (2003), Punta Thurwieser (2004), the Drus west face (2005) and Dents du Midi (2006) are the most recent examples, while innumerable smaller rock falls have detached from alpine steep rockwalls during the hot summer of 2003. Because (i) ice was observed in many starting zones; (ii) the mean annual air temperature (MAAT) in the Alps has increased in more than 1°C during the 20th Century; (iii) the warming trend has accelerated since 1980, the hypothesis of a relation between permafrost changes and an increase of high mountain rockwall instability gains force.
IntroductionIntroduction
The monitoring sitesThe monitoring sites
Aiming to cover wide climatic, geological, geomorphological, topographic and altitudinal gradients, five monitoring areas have been equipped in the Mont Blanc massif and the Matterhorn (western Alps). Four of them are located in the Mont Blanc massif (Aiguille du Midì; Les Drus; Col d’Entrèves; Col du Peuterey) and one is the south-west face of Matterhorn. In these five areas a total amount of nine measurement sites are instrumented; in each site, sensors have been placed in different exposition, fracturation density and steepness (snow cover) context, with the purpose to investigate the effect of such variables on rockwall thermal regimes.
Location of Matterhorn sites
1 - Carrel hut site (CC) 2 - Cheminée (CHEM) 3 - Oriondè (O)CCS
CCW
Carrel Hut
Oriondè
Location of Mont Blanc massif sites
4 - Pilier d’angle (CPS)
5 - Aiguille Blanche (CPN)
6 - Les Drus (DRN + DRS)
7 - Aiguille d’Entrèves (CEN)
8 - Tour Ronde (CES)
9 - Aiguille du Midì (AdM)
4
5
98
6 7
1
1
Matterhorn south face landscape
Carrel hut North-West site
Carrel hut South site
Cheminée
Carrel hut (m3830)
CHEM
2
Cheminée site
OFRONFR
3
Oriondé: high and low fractured
The research project: The research project: objectives and organizationobjectives and organization
‘‘Development of a database and monitoring methodsfor slope instabilities and rock temperatures
in steep alpine rockwalls affected by permafrost’’
INTERREG IIIA France/Italy Project # 196 (03/2006 – 03/2008)
PERMAdataROCPERMAdataROC
3 Work Packages
CENSI_CROCENSI_CRO PERMA_TEMPPERMA_TEMP PERMA_CROPERMA_CRO
Action 1: CENSI_CROAction 1: CENSI_CROCollection, maintenance and analysis of past and recent rock fall/avalanches in the Mont Blanc massif in a data base, based on: (i) systematic survey of slope instability events, (ii) digitalisation of the events in a GIS, (iii) analysis of the topographical, geological and climatic parameters of the affected rockwalls.
Installation of a network of observers (alpine guides, hut keepers, excursionist …)
- Present-day events
1. Event : form filled
2. Form checking (+ field study)
3. Forms database + GIS
4. Analysis of events
- Past events
Past and present scientific studies, local newspapers, alpine journals, hut books, interviews of alpine guides…
Database + GIS
Action 3: PERMA_CROAction 3: PERMA_CROMonitoring of the morphological activity on representative rockwalls, at 9 sites on Mont Blanc massif and Matterhorn, by: (i) frequently repeated surveys with long-range ground-based laserscan (LIDAR) and terrestrial photogrammetry; (ii) installation of a geophone network in one of the study site to determine the frequency and volume of rock falls.
DEM author P.Vacher
- Terrestrial photogrammetry
- Terrestrial LIDAR
Point-clouds(5 cm point spacing)
TIN mesh (Triangular Integrated Network)
DEM(Digital Elevation Model)
Aiguille du Midi (Piton Central) Diachronic comparisonHigh Resolution DEM
Comparison: DEMphoto / DEMLidar
- Location of acoustic emission sources (instability sectors)- Test method for alarm system
Matterhorn: Carrel Hut (3810 m)
4 channels (f=20 KHz)
- Acoustic detection
DEM
Action 2: PERMA_TEMPAction 2: PERMA_TEMPMeasuring and modelling of rockwalls thermal regimes in 9 sites on Mont Blanc massif and Matterhorn in order to asses the effect of global warming, and consequent permafrost degradation, on rockwalls stability. Measured variables at all sites are: rock temperature at different depths (3, 30 and 55 cm), air temperature and relative humidity close to rock-atmosphere interface. Two sites (CC and AdM) have been dedicated to intensive measurements that also include solar radiation (incoming and outgoing short / long wave), wind speed and wind direction. Rock temperature data, in association with meteo-climatic and radiative parameters, will be used to calibrate and validate models of rockwall temperature regimes and their regional distribution in high-mountain areas.
MORE DETAILS on poster “Rockwall thermal regime characterization in high mountain areas Rockwall thermal regime characterization in high mountain areas and related permafrost degradation: preliminary data from the western alpsand related permafrost degradation: preliminary data from the western alps” in this session
International Union of Geodesy and Geophysics XXIV Perugia, Italy 2-13 July, 2007
Philip Deline (1), Edoardo Cremonese (2), Umberto Morra di Cella (2), Paolo Pogliotti (3,2), and the PERMAdataROC Team.1. EDYTEM Lab - Université de Savoie, France 2. ARPA Valle d’Aosta A. O. Cambiamenti Climatici, Italia 3. Dipartimento di Scienze della Terra, GEOSITLAB, Università degli studi di Torino, Italia
Contact: [email protected]
Recent rock falls and permafrost degradationRecent rock falls and permafrost degradation
is the degradation of permafrost in high mountain steep rockwalls, a triggering factor for rock avalanche activity?
is it already in action an acceleration of the permafrost degradation in high mountain steep rockwalls?
Water run-off and/or ice body in rock falls scars was observed... questions:
- Currently frequency and volume of instability events in high mountains are still poorly known because of the lack of systematic observations. - Ongoing permafrost changes in rockwalls remain poorly understood because of the difficulties in carrying on in situ measurements. - So far, permafrost studies in such environments are mainly based on modelling with a few existing instrumented sites. ICE M
atte
rhor
n (
2003
)
Mat
terh
orn
(20
03)
Les
Dru
s (2
005)
Th
urw
iese
r (2
004)
Bre
nva
(19
97)
Des
crip
tion
eve
nt’
s fo
rm
GIS
an
alys
isE
ven
t’s
geor
efer
enti
atio
n
