Recent speed‐up of an alpine rock glacier: an updated chronology of the kinematics of outer hochebenkar rock glacier based on geodetic measurements

Abstract

M., 2016. Recent speed-up of an Alpine rock glacier: an updated chronology of the kinematics of Outer Hochebenkar rock glacier based on geodetic measurements. ABSTRACT.Surface velocities have been regularly monitored at the rock glacier in Outer Hochebenkar,Ötztal Alps, Austria since the early 1950s. This study provides an update to previously published surface velocity time series, showing mean profile velocities of four cross profiles since the beginning of the measurements (1951,1954, 1997; depending on the profile), as well as single block displacements from 1998 to 2015. Profiles P1, P2 and P3 have moved between 42 and 90 m, at mean velocities between 0.70 and 1.48 m yr -1 , since they were first established in the early 1950s (1951/54). Profile P0, established in 1997, has since moved 13 m or 0.75 m yr -1 . An acceleration can be observed at all profiles since the late 1990s, with a particularly sharp velocity increase since 2010. All profiles reached a new maximum velocity in 2015, with 1.98 m yr -1 at the slowest profile (P0) and 6.37 m yr -1 at the fastest profile (P1).Year-to-year variations in profile velocities cannot be clearly attributed to inter-annual variations of climatic parameters like mean annual air temperature, summer temperature, positive degree days, or precipitation. However, higher correlation is found between velocities and cumulative anomalies of air temperature (mean annual air temperature and positive degree days) and summer precipitation, suggesting that these parameters play a key role for the movement of the rock glacier. The lower profiles (P0, P1) show more pronounced year-to-year variations than the upper profiles (P2, P3). It is considered likely that processes other than climatic forcing (e.g. sliding, topography) contribute to the different velocity patterns at the four profiles.

Recent Acceleration of a Rock Glacier Complex, Ádjet, Norway, Documented by 62 Years of Remote Sensing Observations

“…Our hypothesis is that the displacements may be taking place along internal shear zones, retrogressively propagating higher up on the rock glacier (as seen in Movie S3). Similar dynamics is described by Gorbunov et al () for the Burkutty rock glacier and by Hartl et al () for the Outer Hochebenkar rock glacier.…”

The Dösen Rock Glacier in Central Austria: A key site for multidisciplinary long-term rock glacier monitoring in the Eastern Alps

“…DEMs kindly provided by Land Kärnten/KAGIS.______________________________________________________________________________________________ thermal conditions, nourishment processes, landform genesis or landform age. The few intensively studied rock glaciers in Austria are the Reichenkar (Krainer and Mostler, 2000;Hausmann et al, 2007), the Ölgrube, the Kaiserberg (Berger et al, 2004;Hausmann et al, 2012) and the Outer Hochebenkar (Schneider and Schneider, 2001;Hartl et al, 2016) rock glaciers in western Austria. Furthermore, the Hinteres Langtalkar (Avian et al, 2005;Kellerer-Pirklbauer and Kaufmann, 2017), the Weissenkar (Kellerer-Pirklbauer and and the Dösen Rock Glacier (e.g.…”

Multi‐temporal 3D point cloud‐based quantification and analysis of geomorphological activity at an alpine rock glacier using airborne and terrestrial LiDAR

“…Processes related to rock glacier flow are influencing factors of surface changes in many areas of the lower tongue area. Hence, temporal variations could be attributed to increasing flow rates observed since 2009 and an enhancement of related processes of deformation . Intensified thaw‐induced surface changes between 2011 and 2016 may also contribute to temporal variations.…”

“…This would also enable us to more reliably interpret tendencies towards higher surface change rates as indicated by the dynamics observed on the AHK rock glacier in the second half of the observation period. Moreover, the development of area‐wide single boulder detection and tracking can increase the understanding of surface change processes on objects such as the AHK rock glacier examined in this study . For this purpose, high‐resolution point clouds derived from UAV‐borne laser scanning could also provide valuable information.…”

“…The Äußeres Hochebenkar (AHK) rock glacier (Figure ) serves as a good test site for the application of our approach and for a comparison of related analysis results with previous findings because of the existing extensive and continuous research studies . The active tongue‐shaped, bouldery talus rock glacier is situated in the southern Ötztal Alps about 4.3 km SSW of Obergurgl (46°50′11″N, 11°00′20″E), Austria at a NW‐oriented glacial cirque, surrounded by the near‐vertical slopes (up to 300 m high) of Hangerer (3021 m a.s.l.)…”