Abstract Scouring and mass failure are two common mechanisms used to describe soil bed erosion, but their combined effects are often not considered. To better understand how these mechanisms compete and under what conditions they prevail, it is essential to consider infiltration and a more realistic unsaturated soil bed. This study investigates soil bed erosion by considering unsaturated soil mechanics, a wetting front, and both erosion mechanisms of scouring and mass failure. Physical experiments were conducted on model water runoff over an unsaturated sand bed to investigate the effects of s ..read more

Abstract Rock glaciers are common in alpine landscapes, but their evolution over time and their significance as agents of debris transport are not well-understood. Here, we assess the movement of an ice-cemented rock glacier over a range of timescales using GPS surveying, satellite-based radar, and cosmogenic 10Be surface-exposure dating. GPS and InSAR measurements indicate that the rock glacier moved at an average rate of ∼10 cm yr−1 in recent years. Sampled boulders on the rock glacier have cosmogenic surface-exposure ages from 1.2 to 10 ka, indicating that they have been exposed s ..read more

Abstract Capes and cape-associated shoals represent sites of convergent sediment transport, and can provide points of relative coastal stability, navigation hazards, and offshore sand resources. Shoal evolution is commonly impacted by the regional wave climate. In the Arctic, changing sea-ice conditions are leading to (a) longer open-water seasons when waves can contribute to sediment transport, and (b) an intensified wave climate (related to duration of open water and expanding fetch). At Blossom Shoals offshore of Icy Cape in the Chukchi Sea, these changes have led to a five-fold increase in ..read more

Abstract Sediments in steep channels can be mobilized to form stream flows, hyperconcentrated flows and debris flows, which can cause damage to downstream communities. However, the understanding of the sediment-transport mechanisms that control these processes remains incomplete due to the lack of effective monitoring methods. In this study, we utilize seismic data captured during these sediment-laden flows through field experiments and in situ monitoring to offer insights into flow mechanics and sediment transport mechanisms. Results show that sediment transport in stream flows and hyperconce ..read more

Abstract Spectral analysis is a central tool regularly used by the scientific community to identify the presence of periodic processes within a time series of information, as spectral peaks at an imposed periodicity can be differentiated from internal (autogenic) variance. In scientific disciplines, such as seismology, the time series of information is of high temporal resolution. Hence, although temporal gaps are present, they do not impact the overall noise structure, meaning that the full spectrum of autogenic variance can be reconstructed. However, power spectra generated from stratigraphi ..read more

Abstract Ice surface speed increases dramatically from upstream to downstream in many ice streams and glaciers. This speed-up is thought to be associated with a transition from internal distributed deformation to highly localized deformation or sliding at the ice-bedrock interface. The physical processes governing this transition remain unclear. Here, we argue that highly localized deformation does not necessarily initiate at the ice-bedrock interface, but could also take the form of an internal shear band inside the ice flow that connects topographic highs. The power-law exponent n in the ice ..read more

Abstract Observation and measurements of ice structure and deformation made in tunnels excavated into the margin of Taylor Glacier, a polythermal glacier in the McMurdo Dry Valleys of Antarctica, reveal a complex, rapidly deforming basal ice sequence. Displacement measurements in the basal ice, which is at a temperature of −18°C, together with the occurrence of cavities and slickenslides, suggest that sliding or rapid deformation in thin zones of high shear occurs at structural discontinuities within the basal zone. Strain measurements show that the highest strain rates occur in ice with avera ..read more

Abstract The wavelength of aeolian sand ripples increases with wind velocity, but the cause for this increase remained unclear until now. Using numerical simulations, we find that the relationship between the wind strength and the initial wavelength disappears without mid-air collisions, which means that mid-air collisions crucially contribute to the initial wavelength of ripples. As wind strength increases, the average hop length of non-colliding particles decreases. Affected by the bed surface topography and the non-uniform mid-air colliding probability along the wavy surface, non-colliding ..read more

Abstract Over the past decades, seismic monitoring has been increasingly used to track glacial activities associated with ice loss. Many seismological studies focus on West Antarctica, whereas glacial seismicity in East Antarctica is much less studied. Here, we apply unsupervised deep learning to a dense nodal seismic array near Dålk Glacier, East Antarctica, operating from 6 December 2019 to 2 January 2020. An autoencoder is used to automatically extract event features, which are then input into a Gaussian mixture model for clustering. We divide the data into 50 clusters and merge them accord ..read more

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