partly affected the southern Molasse sediments but left most of the basin to the north undeformed. From south to north, geological deposits comprise a limestone fold belt, and imbricated and folded, as well as undeformed, Molasse sediments. The whole area is largely covered by glacial deposits such as moraines and includes partly postglacial erosional features. The area is highly cultivated on the flat terrain, with dense forest on hills and steep slopes, and swamps in former glacial lakes and along rivers. Glacial moraines, which are gravel ridges deposited at the maximum advance of a glacier, remain, along with remnants of overflow and drainage channels that formed when the glaciers melted (right). It is densely covered with infrastructure, including villages and cities. The satellite survey compares well with an extensive ground-based survey reported in 1957, which links the locations of seismic acquisition risks interpreted from the satellite images to a ground truth (below).10
10. See geologic map included in Aberer F: “Die Molassezone im westlichen Oberösterreich und in Salzburg,” Mitteilungen der geologischen Gesellschaft in Wien50 (1957): 23–94 (in German).
Overflow channel Drainage channel Drainage channels
Overflow channel
900
200
05 0
km mi 5
> Austrian moraines. A LiDAR DEM survey shows the variation in elevation in this area of the Alpine foothills. The escarpments (black) were located using an edge-detection algorithm. The two moraines indicate glacial extent. In addition, overflow and drainage channels are apparent in the image. These and the former lake developed as the glacier melted. The white rectangle indicates the location of the more-detailed image in the figure on page 51.
> Ground truth. The interpreted satellite results (color) overlay an extensive ground-based topographic survey (gray scale) reported in 1957 (Aberer, reference 10, used with permission). The remarkable match in the overlay area gives confidence in the location of satellite interpretations.
Winter 2008/2009
49
Moraine Moraine
Former lake
Height, m
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