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| Titel |
Landslides and rock fall processes in the proglacial area of the Gepatsch glacier, Tyrol, Austria - Quantitative assessment of controlling factors and process rates |
| VerfasserIn |
Lucas Vehling, Joachim Rohn, Michael Moser |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076592
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| Zusammenfassung |
| Due to the rapid deglaciation since 1850, lithological structures and topoclimatic factors,
mass movements like rock fall, landslides and complex processes are important contributing
factors to sediment transport and modification of the earth’s surface in the steep,
high mountain catchment of the Gepatsch reservoir. Contemporary geotechnical
processes, mass movement deposits, their source areas, and controlling factors like
material properties and relief parameters are mapped in the field, on Orthofotos and on
digital elevation models. The results are presented in an Arc-Gis based geotechnical
map. All mapped mass movements are stored in an Arc-Gis geodatabase and can
be queried regarding properties, volume and controlling factors, so that statistical
analyses can be conducted. The assessment of rock wall retreat rates is carried out by
three different methods in multiple locations, which differ in altitude, exposition,
lithology and deglaciation time: Firstly, rock fall processes and rates are investigated
in detail on five rock fall collector nets with an overall size of 750 m2. Rock fall
particles are gathered, weighed and grain size distribution is detected by sieving
and measuring the diameter of the particles to distinct between rock fall processes
and magnitudes. Rock wall erosion processes like joint formation and expansions
are measured with high temporal resolution by electrical crack meters, together
with rock- and air temperature. Secondly, in cooperation with the other working
groups in the PROSA project, rock fall volumes are determined with multitemporal
terrestrial laserscanning from several locations. Lately, already triggered rock falls are
accounted by mapping the volume of the deposit and calculating of the bedrock
source area. The deposition time span is fixed by consideration of the late Holocene
lateral moraines and analysing historical aerial photographs, so that longer term
rock wall retreat rates can be calculated. In order to limit homogenous bedrock
sections for calculating specific rock wall retreat rates and to extrapolate the local
determinated rock wall retreat rates to larger scale, bedrock areas will be divided
into units of similar morphodynamic intensities which will be therefore classified
by a rock mass strength (RMS) system. The RMS-System contains lithological
and topoclimatic factors but also takes the measured rock wall retreat rates into
account. |
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