The Reichenkar rock glacier (Tyrol, Austria) is a typical tongue-shaped, 1400 m long, ice-cored active rock glacier, which connects to a debris-free cirque glacier. Aerial photographs from 1954 and 1990 indicate its mean surface velocity to be 0.6 m/a while a photograph from 2003 and annual global positioning system (GPS) measurements since 1998 show that velocities in the past decade have increased to 3 m/a. Integration of ground-penetrating radar (GPR), seismic and gravimetric data reveals that the Reichenkar rock glacier consists of four layers. The uppermost debris layer has an average thickness of about 5 m and is underlain by ice-rich permafrost with an average thickness of about 25 m. A prominent reflector detected by GPR is identified as the top of an unfrozen till layer located a few metres above the bedrock. Seismic refraction data clearly indicate the boundary between till and bedrock. The geophysical interpretation shows that the ice-rich permafrost of the rock glacier has an ice content of 45-60%, depending on assumptions concerning the air content of the ice. Creep velocities calculated from the geophysical model, ice contents and an extension of Glen's flow law are in good accordance with observed surface velocities.

We use earthquake focal mechanisms to study present‐day deformation and stress in the western part of the Eastern European Alps. We define the following regions, based on seismicity and kinematically compatible focal mechanism types: (1) the northern and western parts of the Dolomites indenter, the western and central Tauern Window, and the northern Alpine margin and foreland lack significant seismicity. (2) The indenter boundaries are characterized by strike‐slip faulting. Based on earthquake and geodetic data, the western and northern indenter boundaries are active sinistral and dextral strike‐slip/oblique slip faults. (3) West and north of the indenter corner, we observe normal and strike‐slip faulting in an up to 70 km‐wide zone. From west to east, the minimum horizontal stress rotates clockwise about 10–20°, from NE to ENE. (4) North of (3), east of the Swiss/Austrian border, we find evidence for N to NNW directed thrust faulting, and local orogen‐parallel extension. From our results and geodetic data, we infer that relative to a fixed northern foreland, NNW directed indentation is transferred at depth via the Sub‐Tauern thrust system to this 100‐km‐wide zone of localized thrusting. A lack of evidence for major, active strike‐slip faulting north of the Tauern Window is in line with geodetic data, which show no significant velocity difference between the northern part of the Eastern Alps and their foreland.

Ortles mountain (3905 m a.s.l.), South Tyrol, Italy, is the highest mountain of the Eastern European Alps, and its upper glacier, Alto dell’Ortles, presents a unique opportunity to obtain the first paleoenvironmental record from an ice core in this area. To study the suitability of this glacier as a drilling site, in 2009 we performed the first preliminary study of its glaciological characteristics at ˜3830 m a.s.l. The maximum thickness is ˜75 m, and lamination of the exposed ice layers is excellent down to bedrock. Firn and ice lenses were observed in a 10 m shallow core, and the firn/ice transition was below ˜24m. The seasonal chemical signal is clearly preserved only within the uppermost 2008 and 2009 snow/firn. A simple mass-balance model, the incipient ‘smoothing’ of the chemical record, and the observed ice lenses provide evidence that melting, infiltration and refreezing cycles occurred within the firn layers formed before 2008. Nevertheless, the mass balance of the upper part of Alto dell’Ortles was positive (˜800mma_1) during the last few years. We suggest that an environmental history is likely to be well preserved only within the ice layers formed before ˜1980, when summer air temperature was ˜2°C colder than today in this area. Clearly the continued warming trend predicted to occur over the next few decades, and the consequent increase in frequency and/or intensity of infiltration processes, will endanger the preservation of the glacial archive conserved in the deep ice layers of Ortles mountain.

Permafrost in high alpine catchments is expected to disappear in future warmer climates, but the hydrological impact of such changes is poorly understood. This paper investigates the flow paths and the hydrological response in a 5 km2 high alpine catchment in the Ötztal Alps, Austria, and their changes resulting from a loss of permafrost. Spatial permafrost distribution, depth to the permafrost table, and depth to the bedrock were mapped by geophysical methods. Catchment runoff and meteorological variables were monitored from June 2008 to December 2011. These data were used along with field experience to infer conceptual schemes of the dominant flow paths in four types of hillslopes that differ in terms of their unconsolidated sediment characteristics and the presence of permafrost. The four types are: talus fans, rock glaciers, Little Ice Age (LIA) till, and pre‐LIA till. Permafrost tends to occur in the first three types, but is absent from pre‐LIA till. Based on these flow path concepts, runoff was simulated for present conditions and for future conditions when permafrost has completely disappeared. The simulations indicate that complete disappearance of permafrost will reduce flood peaks by up to 17% and increase runoff during recession by up to 19%. It is argued that change modeling needs to account for flow path types and their changes based on geophysical surveys and field investigations.

Abstract. Several caves in high elevated alpine regions host up to several meters thick ice. The age of the ice may exceed some hundreds or thousands of years. However, structure, formation and development of the ice are not fully understood and are subject to relatively recent investigation. The application of ground-penetrating radar (GPR) enables to determine thickness, volume, basal and internal structure of the ice and provides as such important constraints for related studies. We present results from four caves located in the Northern Calcareous Alps of Austria.We show that the ice is far from being uniform. The base has variable reflection signatures, which is related to the type and size of underlying debris. The internal structure of the cave ice is characterized by banded reflections. These reflection signatures are interpreted as thin layers of sediments and might help to understand the ice formation by representing isochrones. Overall, the relatively low electromagnetic wave speed suggests that the ice is temperate, and that a liquid water content of about 2% is distributed homogenously in the ice.