Geoinformation for Disaster and Risk Management - ISPRS

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Figure 6: Variations of the horizontal position during a representative day. Depicted are the
15min. solutions of SN #3 where all outliers are eliminated and the gaps are closed.
Figure 7a: Medium-term trend of SN #2 (moving average filter of 6 hours between February
and December 2009). Even small movements (in downhill direction) are quite clear. The
estimated movement rates of the slide from former sporadic measurements are at the order of
2cm per year which can be confirmed by the developed system. However, small gaps due to
system breakdown and other failures in March and December can also be seen.
Figure 7b: Medium-term trend of SN #3 (moving average filter of 6 hours between February
and December 2009). For interpretation see text at Fig7a.
In order to predict long term trends of the
deformation process the use of longer filter intervals,
e.g. 6 hours, is applicable. Referring to Fig. 7a and 7b
even small movements are clearly become visible,
e.g. in springtime under the influence of snow melt
(April May) or periods of heavy rainfall (which
occurred at the end of June 2009 in the Alps).
The depicted results of the LC PDGNSS monitoring
system and especially the fact that measuring data is
available in near real-time with a high spatialtemporal
resolution, allows further geological
assessment and interpretation of the landslide. In
combination with data from other systems (e.g. TDR,
video-tacheometer and weather station at
Aggenalm) an additional benefit for geo-mechanical
models and prediction of collapse can be obtained by
an integrative analysis. In contrast to relative
measurement methods such as TDR in boreholes or
extensometers for the surveillance of cleavings,
PDGNSS provides absolute 3D positions allowing
reliable statements about absolute motions and the
precise direction in space. The developed LC PDGNSS
monitoring component therefore can be seen as a
key system for economic landslide monitoring.
However, further effort has to be made to increase
reliability and accuracy. The actual work
concentrates on a comprehensive quality
management and on developing additional
processing and estimation procedures within the
CCA.