Quantitative analysis of rock glacier creep by means of digital photogrammetry using multi-temporal aerial photographs: two case studies in the Austrian Alps

TLDR: In this article, the authors present a special method of measuring surface deformation and flow velocity of creeping rock glaciers based on digital photogrammetry, which is not carried out in the space of the original photos but in quasi-orthophotos derived from the use of rough and preliminary digital terrain models.

Abstract: This paper presents a special method of measuring surface deformation and flow velocity of creeping rock glaciers based on digital photogrammetry. The underlying concept of automatic measurement of 3-D surface displacement vectors in time-series of multi-year digital aerial photographs is explained. In contrast to standard photogrammetric procedures, image matching is not carried out in the space of the original photos but in quasi-orthophotos derived from the use of rough and preliminary digital terrain models. A software package called ADVM (Automatic Displacement Vector Measurement), written in Visual C for running on a Windowsbased PC, has been developed. The software has been tested within the framework of two case studies which comprise the spatio-temporal analysis of the kinematic behavior of three active rock glaciers in the Austrian Alps. The adjacent Inneres and Aeusseres Hochebenkar rock glaciers in the Oetztal Alps and the Hinteres Langtalkar rock glacier located in the Schober group, Hohe Tauern range, are investigated. Selected results of the photogrammetric evaluation are presented numerically and graphically. Permafrost, Phillips, Springman & Arenson (eds) © 2003 Swets & Zeitlinger, Lisse, ISBN 90 5809 582 7