The uppermost part of permanently frozen ground can thaw during summer and refreeze during winter. We use a method based on naturally generated seismic waves to continuously monitor these changes close to the research settlement of Ny-Ålesund in Svalbard between April and August 2016. Our results reveal some potential pitfalls when interpreting temporal variations in the data. However, we show that a careful data analysis makes this method a very useful tool for long-term permafrost monitoring.

Rivers can raise or lower their beds by depositing or eroding sediments. We combine equations for flow, channel/valley geometry, and gravel transport to learn how climate and tectonics shape down-valley profiles of river-bed elevation. Rivers steepen when they receive more sediment (relative to water) and become straighter with tectonic uplift. Weathering and breakdown of gravel is needed to produce gradually widening river channels with concave-up profiles that are often observed in the field.

The article describes the development of a portable triangle control target to register structure-from-motion-derived topographic data. We were able to generate sub-millimetre-resolution 3-D models with sub-millimetre accuracy. We verified the accuracy of our models in an experiment and demonstrated the potential of our method by collecting microtopographic data on weathered Moenkopi sandstone in Arizona. The results from our study confirm the efficacy of our method at sub-millimetre scale.

Landscape evolution models (LEMs) aim to capture an aggregation of the processes of erosion and deposition and predict evolving topography. A key aspect of any LEM is how water is chosen to be routed down the surface, which can impact the model results and, importantly, the numerical accuracy. I find that by treating flow as lines within the model domain and by distributing water down all slopes, the results are independent of resolution, pointing to a new method to model landscape evolution.

A single storm event can change the shape of a sandy beach dramatically, but beaches also exhibit a remarkable ability to recover. So how important are storm-driven changes to a beach in the long term? This question affects predictions of future shoreline change. Here we explore signal shredding – when sediment transport erases any signature of outside driving forces. Our results suggest that major storm impacts may tell us little about long-term shoreline change and vice versa.

Quantitative analysis of digital topography is an important part of many modern geologic investigations. We have constructed a series of software tools, the Topographic Analysis Kit (TAK), built on top of the existing TopoToolbox library, to allow for efficient and easy analysis of topography that limits the required computing and domain-specific knowledge necessary to successfully produce robust analyses of topographic data.

This paper presents applications of structure-from-motion photogrammetry in a physical model of a braided river used to quantify morphology change and provide estimates of water depth, as well as image analysis for mapping bed surface texture.

We mapped eight monsoon-related (> 100 m²) and large (> 0.1 km²) landslides in the Nepal Himalayas since 1970. Adding inventories of Holocene landslides, giant landslides (> 1 km³), and landslides from the 2015 Gorkha earthquake, we constrain the size–frequency distribution of monsoon- and earthquake-induced landslides. Both contribute ~50 % to a long-term (> 10 kyr) total erosion of ~2 mm yr^-1, matching the long-term exhumation rate. Large landslides rarer than ¹⁰Be sampling time drive erosion.

This paper examines how an experimental mega-scale beach nourishment ("Sand Motor") contributes to creating favorable conditions for dune development. These conditions, involving a steady supply of wind-blown sand towards space where it can accumulate, are identified using publicly available remote sensing data. It is demonstrated that the Sand Motor supports a high potential for new dunes to develop, but human disturbances may hamper this development, which negatively impacts coastal safety.

Glacial erosion is known to limit the height of midlatitude mountain ranges affected by substantial glaciation during cold periods. Our study examines this phenomenon in the tropics. A new form of hypsometric analysis, along with other evidence, of 10 tropical ranges reveals widespread signs of a perched glacial base level at the ELA. Although glacial influence is moderate to weak in these environments, the evidence suggests that glacial erosion acts to limit the height of tropical ranges.

Monitoring rock slopes for a long time helps to understand the impact of climate change on the alpine environment. Measurements of seismic signals are often affected by external influences, e.g., unwanted anthropogenic noise. In the presented work, these influences are automatically identified and removed to enable proper geoscientific analysis. The methods presented are based on machine learning and intentionally kept generic so that they can be equally applied in other (more generic) settings.

In rockfall hazard assessment, knowledge about the precise flight path of assumed boulders is vital for its accuracy. We present the full reconstruction of artificially induced rockfall events. The extracted information such as exact velocities, jump heights and lengths provide detailed insights into how rotating rocks interact with the ground. The information serves as future calibration of rockfall modelling tools with the goal of even more realistic modelling predictions.

The shape of landscapes is influenced by climate changes, faulting or the nature of the rocks under the surface. One of the most sensitive parts of the landscape to these changes is the river system that eventually adapts to such changes by adapting its slope, the most extreme example being a waterfall. We here present an algorithm that extracts changes in river slope over large areas from satellite data with the aim of investigating climatic, tectonic or geologic changes in the landscape.

In Bangladesh, we measure how water and sediment move through tidal channels in an area heavily impacted by both sea-level rise and the strategies that humans use to adapt. We found that the amount of water moving through the system is largely controlled by the strength of the tides, while the mass of sediment being transported is strongly connected to the season and to a lesser extent the tides. These results are important for developing strategies to protect both human and natural landscapes.

We present a modelling framework for the prediction of gravel-bed braided river evolution. The model is unique in that it simplifies sediment transport through the use of empirically-derived relationships between channel form and flood-scale particle transport distances, or path lengths, which ultimately allow for longer duration model runs with reduced computational demand. We use field surveys on two braided rivers to validate the model at the event, annual, and decadal timescales.

Mountain-building processes are often investigated by assuming a steady state, meaning the balance between opposing forces, like mass influx and mass outflux. This work shows that the Olympic Mountains are in flux steady state on long timescales (i.e., 14 Myr), but the flux steady state could be disturbed on shorter timescales, especially by the Plio–Pleistocene glaciation. The contribution highlights the temporally nonsteady evolution of mountain ranges.

In the last 50 years the Adygine glacier has been subject to relatively fast recession comparable to other glaciers in Tien Shan. As a consequence, a three-level cascade of glacial lakes formed, two of which were categorised as having medium outburst susceptibility. By 2050, the glacier is expected to have shrunk to 56–73 % of its 2012 extent. Further development of the site will result in formation of new lakes and probably also increase of outburst susceptibility due to permafrost degradation.

We studied and mapped uplifted marine terraces in southern Iran that are part of the Makran subduction zone. Our results show that most exposed terraces were formed in the last 35 000–250 000 years. Based on their altitude and the paleo sea-level, we derive surface uplift rates of 0.05–5 mm yr⁻¹. The marine terraces, tilted with a short wavelength of 20–30 km, indicate a heterogeneous accumulation of deformation in the overriding plate.