This study presents a computer vision application of the structure from motion (SfM) technique in three dimensional high resolution gully monitoring in southern Morocco. Due to impractical use of terrestrial Light Detection and Ranging (LiDAR) in difficult to access gully systems, the inexpensive SfM is a promising tool for analyzing and monitoring soil loss, gully head retreat and plunge pool development following heavy rain events. Objects with known dimensions were placed around the gully scenes for scaling purposes as a workaround for ground control point (GCP) placement. Additionally, the free scaling with objects was compared to terrestrial laser scanner (TLS) data in a field laboratory in Germany. Results of the latter showed discrepancies of 5.6% in volume difference for erosion and 1.7% for accumulation between SfM and TLS. In the Moroccan research area soil loss varied between 0.58 t in an 18.65 m² narrowly stretched gully incision and 5.25 t for 17.45 m² in a widely expanded headcut area following two heavy rain events. Different techniques of data preparation were applied and the advantages of SfM for soil erosion monitoring under complex surface conditions were demonstrated.

Since the end of the Little Ice Age (LIA), formerly glaciated areas have undergone considerable changes in their morphodynamics due to external forces and system-internal dynamics. Using multi-temporal high-resolution digital elevation models (DEMs) from different remote sensing techniques such as historical digital aerial images and light detection and ranging (LiDAR), and the resulting DEMs of difference (DoD), spatial erosion and accumulation patterns can be analyzed in proglacial areas over several decades. In this study, several morphological sediment budgets of different test sites on lateral moraines and different long-term periods were determined, covering a total period of 49 years. The test sites show high ongoing morphodynamics, and therefore low vegetation development. A decrease as well as an increase of the mean annual erosion volume could be demonstrated at the different test sites. All test sites show a slope–channel coupling and a decrease in the efficiency of sediment transport from slopes to channels. These developments are generally subject to conditions of increasing temperature, decreasing short-term precipitation patterns and increasing runoff from adjacent mountain streams. Finally, the study shows that sediment is still available on the investigated test sites and the paraglacial adjustment process is still in progress even after several decades of deglaciation (~133 years).

Satellite-based long-term observations of vegetation cover development in combination with recent in-situ observations provide a basis to better understand the spatio-temporal changes of vegetation patterns, their sensitivity to climate drivers and thus climatic impact on proglacial landscape development. In this study we combined field investigations in the glacier forelands of Fürkele-, Zufall- and Langenferner (Ortles-Cevedale group/Eastern Italian Alps) with four different Vegetation Indices (VI) from Landsat scenes in order to test the suitability for modelling an area-wide vegetation cover map by using a Bayesian beta regression model (RStan). Since the model with the Normalized Difference Vegetation Index (NDVI) as predictor showed the best results, it was used to calculate a vegetation cover time series (1986–2019). The alteration of the proglacial areas since the end of the Little Ice Age (LIA) was analyzed from digital elevation models based on Airborne Laser Scanning (ALS) data and areal images, orthophotos, historical maps and field mapping campaigns. Our results show that a massive glacier retreat with an area loss of 8.1 km² (56.9%; LIA–2019) resulted in a constant enlargement of the glacier forelands, which has a statistically significant impact on the degree of vegetation cover. The area covered by vegetation increased from 0.25 km² (5.6%) in 1986 to 0.90 km² (11.2%) in 2019 with a significant acceleration of the mean annual changing rate. As patterns of both densification processes and plant colonization at higher elevations can be reflected by the model results, we consider in-situ observations combined with NDVI time series to be powerful tools for monitoring vegetation cover changes in alpine proglacial areas.

We have analyzed the impact of different forcings, such as rain and seismicity, on slope instabilites on an active volcano. For this, we compiled a catalog of the locations and volumes of rockfalls in the Piton de la Fournaise crater using seismic records. We validated it by comparing the locations and volumes to those deduced from photogrammetric data. We analyzed 10,477 rockfalls, spanning the period 2014 to 2016. This period corresponds to the renewal of volcanic activity after a 41‐month rest. Our analysis reveals that renewed eruptive activity has unsettled the crater edges. External forcings such as rain and seismicity are shown to potentially increase the number and the volume of rockfalls, with a stronger impact on the volume. Preeruptive seismicity seems to be the main triggering factor for the largest volumes, with a delay of one to several days. Rain alone does not seem to trigger especially large rockfalls. We infer that repetitive vibrations from the many seismic events, combined with the action of rain, induce crack (or slip) growth in highly fractured (or granular) materials, leading to the collapse of large volumes. Regarding their spatial distribution before an eruption, the largest rockfalls seem to migrate toward the location of magma extrusion.

This study focuses on the quantification and analysis of geomorphic processes on the barely vegetated slopes of a recultivated iron ore mine on the Italian island of Elba using photographs from terrestrial laser scanning (TLS) and digital photogrammetry by an unmanned aerial vehicle (UAV) over a period of 5 1/2 years. Beside this, the study tried to work out the potential and the limitations of both methods to detect surface changes by geomorphic process dynamics within a natural environment. Both UAV and TLS show the pattern of the erosion and accumulation processes on the investigated slope quite well, but the calculated amounts differ clearly between the methods. The reasons for these differences could be found in the different accuracies (variable level of detections) of the methods and the different viewing geometries. Both effects have an impact on the detectable process dynamics over different timescales on the slope and their calculated amounts, which in both cases can lead to an underestimation of erosion and accumulation by fluvial processes.

Rock glaciers are cryo‐conditioned downslope‐creeping landforms in high mountains. Their dynamics are changing due to external factors influenced by climate change. Although there has been a growing scientific interest in mountain permafrost and thus in rock glaciers in recent years, their historical development, especially before the first alpine‐wide aerial image flights in the 1950s, has hardly been researched. Therefore, we utilize a historical stereophotogrammetric map from 1922 and historical flow velocity profiles (1938–1953) and relate them to data derived from historical aerial photographs and airborne laser scanning data in several time slices between 1953 and 2021. By doing so, the development of flow velocity, surface elevation changes, and frontal advance of the two lobes of the composite rock glacier Inner Ölgrube, Kaunertal, Austria, is analyzed and compared over almost a century. Results indicate an increased frontal advance in the laterally confined area of one lobe and a severe subsidence in the upper area of both lobes between 1922 and 1953. Whereas the former could be explained by a combination of the short warm phase in the 1940s and 1950s and the (subsurface) topography, the latter might be attributed to the strong melting of superimposed debris‐covered dead ice bodies, a relict of the Little Ice Age (LIA) glaciation. Both factors might also contribute to the increased flow velocities between 1938 and 1953, which are still recognizable in the 1953–1970 time step. Although both lobes follow a general similar trend, which is in line with the alpine‐wide trend of flow velocity acceleration in the 1990s, differences in the geomorphic development of the two lobes were identified. In addition to a slightly varying evolution of the flow velocities, the timing and magnitude of the volume changes are different. Furthermore, both lobes display a dissimilar mechanism of frontal advance over the entire study period. Because the external forcing is identical, the varying development might be attributed to variations in internal structure, bedrock topography, or upslope connection of the lobes. Due to the lateral constriction, the subsurface topography, and the LIA maximum extent of the glacier, it is assumed that the geomorphic development of the Innere Ölgruben rock glacier, particularly before 1953, represents a special case, and the results are not simply transferable to other rock glaciers.