Surficial sediment remobilization by shear between sediment and water above tsunamigenic megathrust ruptures: experimental study Earth Surface Dynamics DOI 10.5194/esurf-13-341-2025 13 May 2025 We propose a new mechanism of co-seismic sediment entrainment induced by shear stress at the sediment–water interface during major subduction earthquakes rupturing to the trench. Physical experiments show that flow velocities consistent with long-period earthquake motions can entrain synthetic marine sediment, and high-frequency vertical shaking can enhance this mobilization. They validate the proposed entrainment mechanism, which opens new avenues for paleoseismology in deep-sea environments. Read more
Channel concavity controls planform complexity of branching drainage networks Earth Surface Dynamics DOI 10.5194/esurf-12-1347-2024 10 December 2024 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. Read more
Testing floc settling velocity models in rivers and freshwater wetlands Earth Surface Dynamics DOI 10.5194/esurf-12-1267-2024 11 November 2024 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. Read more
Barchan swarm dynamics from a Two-Flank Agent-Based Model Earth Surface Dynamics DOI 10.5194/esurf-12-1205-2024 25 October 2024 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. Read more
Sourcing and long-range transport of particulate organic matter in river bedload: Río Bermejo, Argentina Earth Surface Dynamics DOI 10.5194/esurf-12-907-2024 19 August 2024 The transport of plant debris in rivers is an important part of the global carbon cycle and influences atmospheric carbon levels through time. We sampled plant debris at the bed of a lowland river and determined the sources as it is transported hundreds of kilometers. Plant debris can persist at the riverbed, but mechanical breakdown reduces its amount, and it is only a small fraction compared to the suspended load. This plant debris and transport patterns need further investigation globally. Read more
Geomorphic risk maps for river migration using probabilistic modeling – a framework Earth Surface Dynamics DOI 10.5194/esurf-12-691-2024 10 June 2024 In this paper, we propose a framework for generating risk maps that provide the probabilities of erosion due to river migration. This framework uses concepts from probability theory to learn the river migration model’s parameter values from satellite data while taking into account parameter uncertainty. Our analysis shows that such geomorphic risk estimation is more reliable than models that do not explicitly consider various sources of variability and uncertainty. Read more
Influence of cohesive clay on wave–current ripple dynamics captured in a 3D phase diagram Earth Surface Dynamics DOI 10.5194/esurf-12-231-2024 19 January 2024 The seabed can change its shape from flat to undulating, known as ripples; the change rate depends on whether the bed is composed of sticky mud. This study, based on experiments, shows a strong reduction in ripple size when the initial mud content is over 10.6 %. This could help geologists better interpret ancient sea conditions. We present a new model to predict ripple size by considering sticky mud. It should help engineers to describe the behaviour of the seabed when sticky mud is present. Read more
Geomorphological and hydrological controls on sediment export in earthquake-affected catchments in the Nepal Himalaya Earth Surface Dynamics DOI 10.5194/esurf-12-135-2024 5 January 2024 Using satellite images, we show that, unlike other examples of earthquake-affected rivers, the rivers of central Nepal experienced little increase in sedimentation following the 2015 Gorkha earthquake. Instead, a catastrophic flood occurred in 2021 that buried towns and agricultural land under up to 10 m of sediment. We show that intense storms remobilised glacial sediment from high elevations causing much a greater impact than flushing of earthquake-induced landslides. Read more
Alpine hillslope failure in the western US: insights from the Chaos Canyon landslide, Rocky Mountain National Park, USA Earth Surface Dynamics DOI 10.5194/esurf-11-1251-2023 4 December 2023 In this paper, we investigate the 28 June 2022 collapse of the Chaos Canyon landslide in Rocky Mountain National Park, Colorado, USA. We find that the landslide was moving prior to its collapse and took place at peak spring snow melt; temperature modelling indicates the potential presence of permafrost. We hypothesize that this landslide could be part of the broader landscape evolution changes to alpine terrain caused by a warming climate, leading to thawing alpine permafrost. USA">Read more
Constraints on long-term cliff retreat and intertidal weathering at weak rock coasts using cosmogenic 10Be, nearshore topography and numerical modelling Earth Surface Dynamics DOI 10.5194/esurf-11-429-2023 2 June 2023 This study uses a coastal evolution model to interpret cosmogenic beryllium-10 concentrations and topographic data and, in turn, quantify long-term cliff retreat rates for four chalk sites on the south coast of England. By using a process-based model, clear distinctions between intertidal weathering rates have been recognised between chalk and sandstone rock coast sites, advocating the use of process-based models to interpret the long-term behaviour of rock coasts. Read more