Geoscience Reference
In-Depth Information
In a volume dedicated to earth-observing space photogrammetry and
its application to mountain cartography, Robert Kostka investigated the
potential of spaceborne stereo-photography for glaciological purposes
and demonstrated it with detailed mappings of glacial lakes and their
surroundings in the Khumbu Himal and the South Tibetan Pekhu Tso area
(Kostka 1987). In the same volume Manfred Buchroithner (Buchroithner
1987) issued so far unpublished additional details about catastrophic GLOFs
in the Nepalese Himalaya described in previous papers (Buchroithner et al.
1982, Buchroithner 1984a, 1984b, 1985, Danninger and Posch 1986). In 1988
and 1991 the Soviet glaciologist N.V. Popov reported a study earlier already
published in Russian, concerning the control of PDGLs in the Northern Tien
Shan (Popov 1988, 1991).
Subsequently, in 1990—and maybe triggered by Ives' report—one
of the fi rst regional inventories of PDGLs in the form of a small-scale
map was made for ICIMOD by Manfred Buchroithner on the initiative of
Surendra Shrestha, then founder and head of MENRIS and later Director
of UNEP-EAP. This 'Jokulhlaup Hazard Map' was, however submitted
as an internal copy for ICIMOD and only published several years later in
a diminished form (Buchroithner 1996). Based on December 1982 high-
resolution stereoscopic colour-infrared Metric Camera imagery taken from
the NASA Space Shuttle that covered the High Himalaya region south of the
Lhasa-Kathmandu Friendship Highway between Kodari in the West and
the eastern border of Sikkim and identifi ed clusters of 162 risk sites with
surfi cial PDGLs. This map-preparation was based on in-depth fi eld- and
offi ce experiences of the author from his studies carried out in the 1980s
(Buchroithner 1984a, 1984b, 1985).
It is remarkable that in all three cases of these described fl ash-fl ood
traces, their places of origin were situated in areas where major geological
lineaments intersect minor ones. This observation suggests that tectonic
forces, i.e., earthquakes, could, in the very fi rst instance, be responsible for
these catastrophes (Buchroithner 1984b).
Calculation of the real, non-projective area eroded during the fl ash-
fl ood event detected by Manfred Buchroithner in the upper Tamur River
yielded an acreage of some 479000 m², a fi gure 92000 m² (24%) larger than
the projective area (Buchroithner 1985). The possibility to calculate real
areas and, consequently, also volumes by prior- and post-state comparisons,
clearly demonstrates the potential of photogrammetric space imagery, in
the above case of Metric Camera photographs. In particular for high-relief
terrain it is essential to refer not only to the nadir-projective but—fi rst of
all—to the real acreage.
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