Loose grains travel farther after a fire because no vegetation is left to stop them. This matters since loose grains at the base of a slope can turn into a debris flow if it rains. To find if grass growing back after a fire had different impacts on grains of different sizes on slopes of different steepness, we dropped thousands of natural grains and measured how far they went. Large grains went farther 7 months after the fire than 11 months after, and small grain movement didn’t change much.

Fluvial terraces and alluvial fans in the Toro Basin, NW Argentina, record river evolution and global climate cycles over time. Landform dating reveals lower-frequency climate cycles (100 kyr) preserved downstream and higher-frequency cycles (21/40 kyr) upstream, supporting theoretical predications that longer rivers filter out higher-frequency climate signals. This finding improves our understanding of the spatial distribution of sedimentary paleoclimate records within landscapes.

Overdeepenings are bedrock depressions filled with sediment. We combine the results of a gravity survey with drilling data to explore the morphology of such a depression beneath the city of Bern. We find that the target overdeepening comprises two basins >200 m deep. They are separated by a bedrock riegel that itself is cut by narrow canyons up to 150 m deep. We postulate that these structures formed underneath a glacier, where erosion by subglacial meltwater caused the formation of the canyons.

To explore the pattern formed by rivers as they crisscross the land, we developed a way to measure how these patterns vary, from straight to complex, winding paths. We discovered that a river's degree of complexity depends on how the river slope changes downstream. Although this is strange (i.e., why would changes in slope affect twists of a river in map view?), we show that this dependency is almost inevitable and that the complexity could signify how arid the climate is or used to be.

This study explores the fluvial morphology evolution in three rivers in Taiwan caused by natural tectonic movements (the 1999 M_w 7.6 Chi-Chi earthquake) and human-made structures (dams). Knickpoints resulting from riverbed uplift shift, leading to gradual evolution from instability to equilibrium. Dams, on the other hand, cause continuous degradation of the bed. When both effects exist on a reach, the impact of the knickpoint gradually fades away, but the effects of the dam on the river persist.

Faceted topographies are impressive footprints of active tectonics in geomorphology. This paper investigates the evolution of faceted topographies at normal faults and their interaction with a river network theoretically and numerically. As a main result beyond several relations for the geometry of facets, the horizontal displacement associated with normal faults is crucial for the dissection of initially polygonal facets into triangular facets bounded by almost parallel rivers.

We use cutting-edge algorithms and conceptual simplifications to solve the equations that describe surface water flow. Using quantitative data on rainfall and elevation, GraphFlood calculates river width and depth and approximates erosive power, making it a suitable tool for large-scale hazard management and understanding the relationship between rivers and mountains.

Fine sediment grains in freshwater can cohere into faster-settling particles called flocs, but floc settling velocity theory has not been fully validated. Combining three data sources in novel ways in the Wax Lake Delta, we verified a semi-empirical model relying on turbulence and geochemical factors. For a physics-based model, we showed that the representative grain diameter within flocs relies on floc structure and that heterogeneous flow paths inside flocs increase floc settling velocity.

Suspended-sand fluxes in rivers vary with time and space, complicating their measurement. The proposed method captures the vertical and lateral variations of suspended-sand concentration throughout a river cross-section. It merges water samples taken at various positions throughout the cross-section with high-resolution acoustic velocity measurements. This is the first method that includes a fully applicable uncertainty estimation; it can easily be applied to any other study sites.

The time it takes for a landscape to adjust to new environmental conditions is critical for understanding the impacts of past and future environmental changes. We used different computational models and methods and found that predicted times for a landscape to reach a stable condition vary greatly. Our results illustrate that reporting how timescales are measured is important. Modelers should ensure that the measurement technique addresses the question.

Barchans are fast-moving sand dunes which form large populations (swarms) on Earth and Mars. We show that a small range of model parameters produces swarms in which dune size does not vary downwind – something that is observed in nature but not when using earlier models. We also show how the shape of dunes and the spatial patterns they form are affected by wind direction. This work furthers our understanding of the interplay between environmental drivers, dune interactions, and swarm properties.

Toma hills are relatively isolated hills found in the deposits of rock avalanches, and their origin is still enigmatic. This paper presents the results of numerical simulations based on a modified version of a friction law that was originally introduced for snow avalanches. The model produces more or less isolated hills (which look much like toma hills) on the valley floor. The results provide, perhaps, the first explanation of the occurrence of toma hills based on a numerical model.

MassWastingRunout (MWR) is a new landslide runout model designed for sediment transport, landscape evolution, and hazard assessment applications. MWR is written in Python and includes a calibration utility that automatically determines best-fit parameters for a site and empirical probability density functions of each parameter for probabilistic model implementation. MWR and Jupyter Notebook tutorials are available as part of the Landlab package at https://github.com/landlab/landlab.

Climate change is a hot topic and changes in storminess can be indicative of climate change impacts. Also, coastal storms can impact ecosystems and the people who live, work, and recreate along our world's coasts. Our findings show that the number of the US east coast storms has not increased since the early 20th century, but storm strength has increased moderately. Finally, beaches can take up to 10 years to recover depending on the number, timing, and strength of previous storms.

This study investigates the use of optical PlanetScope data for offset tracking of the Earth's surface movement. We found that co-registration accuracy is locally degraded when outdated elevation models are used for orthorectification. To mitigate this bias, we propose to only correlate scenes acquired from common perspectives or base orthorectification on more up-to-date elevation models generated from PlanetScope data alone. This enables a more detailed analysis of landslide dynamics.

Topographic metrics were used to understand changes due to tectonic activity. We evaluated the relative tectonic activity along the Ulsan Fault Zone (UFZ), one of the most active fault zones in South Korea. We divided the UFZ into five segments, based on the spatial variation in activity. We modeled the landscape evolution of the study area and interpreted tectono-geomorphic history during which the northern part of the UFZ experienced asymmetric uplift, while the southern part did not.

Coastal rock cliffs on Svalbard are considered to be fairly stable; however, long-term trends in coastal-retreat rates remain unknown. This study examines changes in the coastline position along Brøggerhalvøya, Svalbard, using aerial images from 1970, 1990, 2010, and 2021. Our analysis shows that coastal-retreat rates accelerate during the period 2010–2021, which coincides with increasing storminess and retreating sea ice.

The rates at which rivers erode their bed can be used to interpret the geologic history of a region. However, these rates depend significantly on the time window over which you measure. We use multiple dating methods to determine an incision rate for the San Juan River and compare it to regional rates with longer timescales. We demonstrate how specific geologic events, such as cutoffs of bedrock meander bends, are likely to preserve material we can date but also bias the rates we measure.