Recent  

We show that Icelandic long runout landslides with longitudinal ridges represent good analogues of martian landforms. The large record of long runout landslides with longitudinal ridges emplaced after the Last Glacial Maximum in Iceland offers a unique opportunity to study the possible relation between the development of these landforms and environmental conditions. This could have implications in reconstructing martian paleoclimatic and paleoenvironmental conditions.

In this manuscript, we investigated the June 28th, 2022 collapse of the Chaos Canyon landslide in Rocky Mountain National Park, Colorado, USA. We found the landslide was moving prior to its collapse, took place at peak spring snowmelt, and temperature modeling indicates the potential presence of permafrost, indicating this collapse could be due to permafrost thaw. We hypothesize this landslide could be part of the broader landscape evolution changes to alpine terrain caused by a warming climate.

Rivers can cut into rocks and their strength modulates the river's erosion rates. Yet, it is poorly understood which properties of the rock control its response to erosive action. Here, we describe parallel experiments to measure rock erosion rates under fluvial impact erosion and the rock's geotechnical properties such as fracture strength, elasticity and density. Erosion rates vary over a factor of million between different rock types. We use the data to improve current theory.

Massive sediment pulses in catchments are a key alpine multi-risks component. Combining high-resolution aerial imagery and seismic information, we decipher a multi-stage >150.000 m³ rockfall and subsequent sediment pulses over 4 years, reflecting sediment deposition up to 10 m, redistribution in the basin, and finally debouchure to the outlet. This study provides generic information on spatial and temporal patterns of massive sediment pulses in highly-charged alpine catchments.

Many steep glaciated rock-walls collapsed when the Ice Age ended. How ice supports a steep rock-wall until the ice decays is poorly understood. A collapsed rock-wall was surveyed in the field and numerically modelled. Cosmogenic exposure-dates show the rock-wall collapsed and became ice-free c. 18 ka ago. The model showed that the rock-wall failed very slowly because ice was buttressing the slope. Dating other collapsed rock-walls will improve understanding of how and when the last Ice Age ended.

River deltas encompass many depositional environments (like channels and wetlands) that interact to produce coastal environments that change through time. The processes leading to sedimentation in wetlands are often neglected from physical delta models. We show that wetland sedimentation constrains flow to the channels, changes sedimentation rates, and produces channels more akin to field-scale deltas. These results have implications for management of these vulnerable coastal landscapes.

Secondary bedforms, that are superimposed on large, primary dunes, likely play a large role in fluvial systems. This study demonstrates they can be omnipresent. Especially during peak flows, they grow large and can have steep slopes, likely affecting flood risk and sediment transport dynamics. Primary dune morphology determines whether they continuously or intermittently migrate. During discharge peaks, the secondary bedforms can become the dominant dune scale.

In glacial landscapes, debris supply rates vary spatially and temporally. Rockwall erosion rates derived from cosmogenic ¹⁰Be concentrations in medial moraine debris at five adjacent Swiss glaciers indicate an increase in erosion from the end of the Little Ice Age towards deglaciation, but temporally more stable rates over the last ~100 years. Rockwall erosion rates are higher where rockwalls are steep and north-facing, suggesting a potential slope and temperature control.

Coastal flooding can cause significant damage to coastal ecosystems, infrastructure and communities, and is expected to increase in frequency with the acceleration of sea level rise. In order to respond to it, it is crucial to measure and model their frequency and intensity. Here, we show Deep-Learning techniques can be successfully used to automatically detect flooding events from complex coastal imagery, opening the way to real-time monitoring and data acquisition for model development.

We provide a detailed characterization of the frequency, intensity and duration of flooding events at a site along the Texas coast that demonstrates the suitability of relatively simple wave run-up models to estimate the frequency and intensity of coastal flooding. Our results validate and expands the first probabilistic model of coastal flooding driven by wave run-up, which can then be used in coastal risk management and coastal response to sea level rise.

The Wei River catchment, one of the centers of the agricultural revolution in China, has experienced intense land use changes since 6000 BCE. This makes it an ideal place to study the response of river systems to anthropogenic land use chage. The modeling results show the sensitivities of discharge and sediment yield to climate change increased abruptly when the agricultural land area exceeded a threshold around 1000 BCE. This regime shift in the fluvial catchment led to a large sediment pulse.

This study explores the fluvial morphology evolution in three rivers in Taiwan caused by natural tectonic movements (the 1999 Mw 7.6 Chi-Chi earthquake) and human-made structures (Dams). Knickpoints resulting from riverbed uplift move, 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 results of the dam on the river persist.

Coastal rock cliffs on Svalbard are considered to be fairly stable, however, long-term trends of coastal retreat rates are unknown so far. This study presents changes in the coastline along Brøgger Peninsula, Svalbard, based on aerial images from 1970, 1990, 2010 and 2021. Our analysis shows that coastal retreat rates accelerate in the time period 2010–2021, which coincides with increasing storminess, retreating sea ice and increasing ground temperatures.

Reliable quantification of sediment transport processes is necessary to understand the fate of shallow tidal environments. Here we present a framework for the description of suspended sediment dynamics to quantify deposition in the long-term modeling of shallow tidal systems. This characterization, together with that of erosion events, allows one to set up synthetic, yet reliable, models for the long-term evolution of tidal landscapes.

Large landslides turn into an avalanche-like mode of flow at high velocities, which allows for a much longer runout than predicted for a sliding solid body. In this study, the Voellmy rheology widely used in models for hazard assessment is reinterpreted and extended. The new approach predicts the increase in runout length with volume observed in nature quite well and may thus be a major step towards a more consistent modeling of rock avalanches and improve hazard assessment.

Sediment erosion induced by wind waves is one of the main drivers of the morphological evolution of shallow tidal environments. However, a reliable description of erosion events for the long-term morphodynamic modelling of tidal systems is still lacking. By statistically characterizing sediment erosion dynamics in the Venice Lagoon over the last four centuries, we set up a novel framework for a synthetic, yet reliable, description of erosion events in tidal systems.

Preservation bias often hampers the extraction of sea level changes from the stratigraphic record. In this contribution, we use a forward stratigraphic model to build three synthetic subtropical fringing reefs for a site in southwestern Madagascar (Indian Ocean). Each of the three synthetic reefs represent a different ice-sheet melt scenario for the Pleistocene. We then evaluate each resultant reef sequence against the observed stratigraphic record.

Two-thirds of the world's most populated cities are situated close to deltas. We use computer simulations to understand how deltas sink or rise in response to climate-driven sea-level changes that operate from thousands to millions of years. Our research shows that because of the interaction between the outer layers of the Earth, sediment transport and sea-level changes deltas develop a self-regulated mechanism that modifies the space they need to gain or lose land.