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Reconstruction of mass accumulation rates (MARs) in loess deposits are widely used for interpreting long‐term aeolian transport and climate dynamics in terrestrial environments. However, these interpretations are often driven by a preponderance of reconstructions from individual or selected sites, which can bias our understanding of past climate, especially in the absence of other proxy information. Recent studies on MARs from multiple loess sites in Arid Central Asia (ACA) reveal disparities in the timing of peaks in accumulation between sites, as well as asynchronies with loess flux in the Chinese Loess Plateau (CLP). We investigate this issue by (1) dating five new sites from the western Ili Basin, therefore extending the spatial cover of loess chronologies across ACA and (2) combining that with MARs from >30 sites across ACA and the CLP over the last 60 ka. Our results indicate spatio‐temporal inhomogeneity in the timing and rate of loess deposition across the ACA, and highlight the importance of interrogating local and regional influences on dust supply and transport. Our synthesis of MARs from ACA and the CLP suggests that the timing of peak dust flux as an indicator of large‐scale climate dynamics is best derived from an aggregate of sites; this removes site‐specific bias where local processes or topographic settings outweigh the climate signature., L Lisá acknowledges the support of internal program No. RVO67985831 of the Institute of Geology CAS, Prague and OP RDE, MEYS under the project ‘Ultra‐trace isotope research in social and environmental studies using accelerator mass spectrometry’, Reg. No. CZ.02.1.01/0.0/0.0/16_019/0000728., This study was funded by an independent Max Planck Research Group awarded by the Max Planck Society to KE Fitzsimmons.

Regional assessments of the wind erosion risk are rare and vary due to the methods used and the available data to be included. The adaptation of existing methods has the advantage that the results can be compared directly. We adopted an already successfully applied methodology (ILSWE—applied in East Africa), to investigate the spatiotemporal variability of the wind erosion risk between 2005 and 2019 in Southern Africa. The approach integrates climatic variables, a vegetation index, and soil properties to describe the potential impact of wind erosion at the landscape scale. The annual and seasonal variability is determined by the vegetation cover, whereas droughts and strong El Niño events had only regional effects. We estimated that 8.3% of the study area experiences a moderate to elevated wind erosion risk over the 15‐year period with annual and inter‐annual fluctuations showing a slight upward trend. In general, the desert and drylands in the west have the highest proportion of risk areas, the moist forests in the east are characterized by a very low risk of wind erosion, while the grasslands, shrublands, and croplands in the interior most likely react to changes of climatic conditions. The validation process is based on a comparison with the estimated frequency of dust storms derived from the aerosol optical depth and angstrom exponent and revealed an overall accuracy of 65%. The results of this study identify regions and yearly periods prone to wind erosion to prioritize for further analysis and conservation policies for mitigation and adaptation strategies., Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347, German Federal Ministry of Education and Research (BMBF), http://www.climatologylab.org/terraclimate, https://www.isric.org/, http://www.fao.org/soils-portal/data-hub/soil-maps-and-databases/harmonized-world-soil-database-v12, https://land.copernicus.eu/global/products/fcover, https://www.esa-landcover-cci.org/%20, https://databasin.org/, https://giovanni.gsfc.nasa.gov/giovanni/

Process‐based model ling has long been used as a well‐suited tool to simulate soil erosion. Despite a large number of scientific articles that emphasize the role of compacted tramlines for soil erosion and surficial nutrient transport, no study exists that integrates these artificial structures into process‐based modelling at catchment scales. Thus, this study aims to quantify the effects of tramline compaction on soil erosion dynamics within a catchment. For this reason, high‐resolution spatial data (1 × 1 m) have been incorporated into the model EROSION 3D, which was used, calibrated, and tested for a soil erosion event with measured discharge and soil loss data. To quantify the contribution of tramlines to soil erosion, two different model parameterizations have been used: the tramline parameterization (TLP) and the common model parameterization (CP) that disregards the tramlines. The results reveal that: (i) the parameterization of tramlines improved model outcomes; (ii) tramlines significantly contribute to overall soil loss and sediment entrance into the channel network; (iii) the bulk density of tramlines is the most important driver of increases in soil erosion and runoff. Moreover, our investigation suggests that the impact of compacted tramlines have long been underestimated in soil erosion modelling and can assist in the assessment of surficial flow path connectivity. Thus, the integration of tramlines into soil erosion modeling is important for the implementation of adequate soil conservation and water protection measures., Federal Ministry of Education and Research (within the BonaRes Framework) http://dx.doi.org/10.13039/501100002347, https://doi.org/10.5281/zenodo.5153427

Fluvial aggradation and incision are often linked to Quaternary climate cycles, but it usually remains unclear whether variations in runoff or sediment supply or both drive channel response to climate variability. Here we quantify sediment supply with paleo-denudation rates and provide geochronological constraints on aggradation and incision from the Sfakia and Elafonisi alluvial-fan sequences in Crete, Greece. We report seven optically stimulated luminescence and ten radiocarbon ages, eight Be-10 and eight Cl-36 denudation rates from modern channel and terrace sediments. For five samples, Be-10 and Cl-36 were measured on the same sample by measuring Be-10 on chert and Cl-36 on calcite. Results indicate relatively steady denudation rates throughout the past 80 kyr, but the aggradation and incision history indicates a link with climate shifts. At the Elafonisi fan, we identify four periods of aggradation coinciding with Marine Isotope Stages (MIS) 2, 4, 5a/b, and likely 6, and three periods of incision coinciding with MIS 1, 3, and likely 5e. At the Sfakia fan, rapid aggradation occurred during MIS 2 and 4, followed by incision during MIS 1. Nearby climate and vegetation records show that MIS 2, 4, and 6 stadials were characterized by cold and dry climates with sparse vegetation, whereas forest cover and more humid conditions prevailed during MIS 1, 3, and 5. Our data thus suggest that past changes in climate had little effect on landscape-wide denudation rates but exerted a strong control on the aggradation-incision behaviour of alluvial channels on Crete. During glacial stages, we attribute aggradation to hillslope sediment release promoted by reduced vegetation cover and decreased runoff; conversely, incision occurred during relatively warm and wet stages due to increased runoff. In this landscape, past hydroclimate variations outcompeted changes in sediment supply as the primary driver of alluvial deposition and incision., Earth Surface Processes and Landforms, 48 (2), ISSN:0197-9337, ISSN:1096-9837

Seasonal variations in landslide activity remain understudied compared to recent advances in landslide early warning at hourly to daily timescales. Here, we learn the seasonal pattern of monthly landslide activity in the Pacific Northwest from five heterogeneous landslide inventories with differing spatial and temporal coverage and reporting protocols combined in a Bayesian multi‐level model. We find that landslide activity is distinctly seasonal, with credible increases in landslide intensity, inter‐annual variability, and probability marking the onset of the landslide season in November. Peaks in landslide probability in January and intensity in February lag the annual peak in mean monthly precipitation and landslide activity is more variable in winter than in summer, when landslides are rare. For a given monthly rainfall, landslide intensity at the season peak in February is up to 10 times higher than at the onset in November, underlining the importance of antecedent seasonal hillslope conditions., Plain Language Summary: Better knowing when landslides are likely over the course of the year can reduce landslide risk by improving emergency preparedness. One research challenge is that catalogs of past landslides rarely cover the same areas or time periods, and have been collected in different ways. Here, we use statistical models to estimate monthly landslide activity in the Pacific Northwest. The models are able to combine five different landslide catalogs to make best use of all available information. We find a seasonal pattern in both the average number of landslides in a month and the probability of having any landslides. The landslide season begins in November, when the average number and the probability of landslides increase. The probability of landslides peaks in January and the average number in February, lagging behind winter rainfall peaks by one to two months. While landslides are least likely in summer, their activity is more variable in winter, with some winters bringing hundreds of landslides, and some very few. At the landslide season peak in February, a comparable amount of rain leads to many more landslides than at the onset in November, likely because already wet hillslopes are more prone to failure., Key Points: Bayesian inference learns the seasonal pattern of landslide activity in the Pacific Northwest from five combined heterogeneous inventories. Landsliding is distinctly seasonal with highest probability (intensity) in January (February), lagging the annual precipitation peak. Landslide intensity for a given monthly rainfall during peak season in February is up to 10 times higher than at the onset in November., DFG RTG NatRiskChange, https://data.nasa.gov/Earth-Science/Global-Landslide-Catalog/h9d8-neg4

A large number of landslide events have repeatedly struck the border zone of the northwestern plateaus of Ethiopia. Debre Sina area is one of the most tectonically active areas located along the western margin of the Afar depression, which is frequently affected by landslides. Despite that, urban and rural development is currently active in almost the entire area. It is crucial, therefore, to understand the main causes and failure mechanisms of landslides in the Debre Sina area and its surroundings. The present study investigated landslides using field mapping of geological and geomorphological features, remote sensing, geo-morphometric analysis, structural analysis, rainfall data, landslide inventory, and earthquake data. The results of the study indicate that large-scale and deep-seated landslide problems appear to be caused by complex geological settings and rugged topography. In particular, the location and morphology of the Yizaba Wein and Shotel Amba landslides are strongly controlled by geological structures. Their flanks are bounded by high angle faults, and their main basal failure surfaces have developed within a W–E striking eastward-dipping normal fault zone. The complex litho-structural and morphologic settings play a vital role in controlling the geometry of the slip surfaces and the stability of the landslides., Research School PLUS, Ruhr University Bochum (DE)

Landslide research relies on landslide inventories for a multitude of spatial, temporal, or process analyses. Generally, it takes high effort to populate a landslide inventory with relevant data. In this context, the present work investigated an effective way to handle vast amounts of automatically acquired digital data for landslide inventories by the use of machine learning algorithms and information filtering. Between July 2017 and February 2019, a keyword alert system provided 4381 documents that were automatically processed to detect landslide events in Germany. Of all those documents, 91% were automatically recognized as irrelevant or duplicates; thereby, the data volume was significantly reduced to contain only actual landslide documents. Moreover, it was shown that inclusion of the document’s images into the automated process chain for information filtering is recommended, since otherwise unobtainable important information was found in them. Compared with manual methods, the automated process chain eliminated personal idiosyncrasies and human error and replaced it with a quantifiable machine error. The applied individual algorithms for natural language processing, information retrieval, and classification have been tried and tested in their respective fields. Furthermore, the proposed method is not restricted to a specific language or region. All languages on which these algorithms are applicable can be used with the proposed method and the training of the process chain can take any geographical restriction into account. Thus, the present work introduced a method with a quantifiable error to automatically classify and filter large amounts of data during automated digital data acquisition for landslide inventories., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Niedersächsische Ministerium für Wissenschaft und Kultur http://dx.doi.org/10.13039/100011937

The timing of the Monte Peron Landslide is revised to 2890 cal. BP based on a radiocarbon-dated sediment stratigraphy of Lago di Vedana. This age fosters the importance of hydroclimatic triggers in the light of accelerating global warming with a predicted increase of precipitation enhancing the regional predisposition to large landslides. Moreover, a layer enriched in allochthonous organic and minerogenic detritus dating to the same wet period is interpreted as response to a younger and yet unidentified mass wasting event in the catchment of Lago di Vedana. Rock debris of the Monte Peron Landslide impounded the Cordevole River valley and created a landslide-dammed lake. Around AD 1150, eutrophication of this lacustrine ecosystem started with intensified human occupation – a process that ended 150 years later, when the river was diverted back into its original bed. Most likely, this occurred due to artificial opening of the river dam. In consequence, Lago di Vedana was isolated from an open and minerogenic to an endorheic and carbonaceous lacustrine system. After a monastery was established nearby in AD 1457, a second eutrophication process was initiated due to intensified land use linked with deforestation. Only in the eighteenth and nineteenth centuries, deposition of organic matter decreased coinciding with climatic (Little Ice Age) and cultural changes. Conversational measures are the likely reasons for a trend towards less eutrophic conditions since AD 1950., Universität Bremen (1013), https://doi.org/10.1594/PANGAEA.937090

Past orbital parameters of the Moon are difficult to reconstruct from geological records because relevant data sets of tidal strata are scarce or incomplete. The sole Archean data point is from the Moodies Group (ca 3.22 Ga) of the Barberton Greenstone Belt, South Africa. From the time‐series analysis of tidal bundles from a well‐exposed subaqueous sand wave of this unit, Eriksson and Simpson (Geology, 28, 831) suggested that the Moon’s anomalistic month at 3.2 Ga was closer to 20 days than the present 27.5 days. This is in apparent accordance with models of orbital mechanics which place the Archean Moon in a closer orbit with a shorter period, resulting in stronger tidal action. Although this study’s detailed geological mapping and section measuring of the site confirmed that the sandstone bed in question is likely a migrating dune, the presence of angular mud clasts, channel‐margin slumps, laterally aggrading channel fills and bidirectional paleocurrents in overlying and underlying beds suggests that this bedform was likely located in a nearshore channel near lower‐intertidal flats and subtidal estuarine bars; it thus carries risk of incomplete preservation. Repeated measurements of foreset thicknesses along the published traverse, measured perpendicular to bedding, failed to show consistent spectral peaks. Larger data sets acquired along traverses measured parallel to bedding along the 20.5 m wide exposure are affected by minor faulting, uneven outcrop weathering, changing illumination, weather, observer bias and show a low reproducibility. The most robust measurements herein confirm the periodicity peak of approximately 14 in the original data of Eriksson and Simpson (Geology, 28, 831). Because laminae may have been eroded, the measurements may represent a lower bound of about 28 lunar days per synodic month. This estimate agrees well with Earth–Moon dynamic models which consider the conservation of angular momentum and place the Archaean Moon in a lower orbit around a faster‐spinning Earth., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

River‐valley morphology preserves information on tectonic and climatic conditions that shape landscapes. Observations suggest that river discharge and valley‐wall lithology are the main controls on valley width. Yet, current models based on these observations fail to explain the full range of cross‐sectional valley shapes in nature, suggesting hitherto unquantified controls on valley width. In particular, current models cannot explain the existence of paired terrace sequences that form under cyclic climate forcing. Paired river terraces are staircases of abandoned floodplains on both valley sides, and hence preserve past valley widths. Their formation requires alternating phases of predominantly river incision and predominantly lateral planation, plus progressive valley narrowing. While cyclic Quaternary climate changes can explain shifts between incision and lateral erosion, the driving mechanism of valley narrowing is unknown. Here, we extract valley geometries from climatically formed, alluvial river‐terrace sequences and show that across our dataset, the total cumulative terrace height (here: total valley height) explains 90%–99% of the variance in valley width at the terrace sites. This finding suggests that valley height, or a parameter that scales linearly with valley height, controls valley width in addition to river discharge and lithology. To explain this valley‐width‐height relationship, we reformulate existing valley‐width models and suggest that, when adjusting to new boundary conditions, alluvial valleys evolve to a width at which sediment removal from valley walls matches lateral sediment supply from hillslope erosion. Such a hillslope‐channel coupling is not captured in current valley‐evolution models. Our model can explain the existence of paired terrace sequences under cyclic climate forcing and relates valley width to measurable field parameters. Therefore, it facilitates the reconstruction of past climatic and tectonic conditions from valley topography., Plain Language Summary: Little is known on how valleys widen and what sets their width. Therefore, it remains difficult to model the wealth of valley geometries that occur in nature and to predict how valleys adjust to environmental changes. Paired river terraces are staircases of abandoned valley floors that preserve valley widths of the past. The formation of river‐terrace sequences requires changes between vertical river incision and lateral river erosion of valley walls. Moreover, to preserve terraces on both sides of the river, the valley has to narrow over time. While cyclic climate changes during the Quaternary can explain the alternations between vertical incision and lateral erosion, they cannot explain why those valleys narrow. Here we investigate past valley geometries in paired, climatically formed river terraces. We find a negative linear relationship between valley width and valley height. We propose that this relationship reflects a balance between sediment that is moved from hillslopes into the channel and the capacity of the river to remove this sediment. Higher valley walls contribute more sediment that protects the wall from further widening. By including this hillslope‐erosion term, valley‐formation models can reproduce paired river terraces, and allow us to work toward “reading” climatic conditions from valley geometries., Key Points: Valley width in alluvial terraces is inversely proportional to valley height. We suggest sediment supply from river‐independent hillslope erosion limits valley width. The coupling of hillslopes and river channels demands revision of current valley‐evolution models., EC H2020 PRIORITY “Excellent science” H2020 Marie Skłodowska‐Curie Actions http://dx.doi.org/10.13039/100010665, https://doi.org/10.5880/fidgeo.2022.021

Large, rarely mobile boulders are observed globally in mountainous bedrock channels. Recent studies suggest that high concentrations of boulders could be associated with channel morphological adjustment. However, a process‐based understanding of large boulder effects on channel morphology is limited, and data are scarce and ambiguous. Here, we develop a theory of steady‐state channel width and slope as a function of boulder concentration. Our theory assumes that channel morphology adjusts to maintain two fundamental mass balances: (a) grade, in which the channel transports the same sediment flux downstream despite boulders acting as roughness elements and (b) bedrock erosion, by which the channel erodes at the background tectonic uplift rate. Model predictions are normalized by a reference, boulder‐free channel width and slope, accounting for variations due to sediment supply, discharge, and lithology. Models are tested against a new data set from the Liwu River, Taiwan, showing steepening and widening with increasing boulder concentration. Whereas one of the explored mechanisms successfully explains the observed steepening trend, none of the models accuratly account for the observed width variability. We propose that this contrast arises from different adjustment timescales: while sediment bed slope adjusts within a few floods, width adjustment takes a much longer time. Overall, we find that boulders represent a significant perturbation to fluvial landscapes. Channels tend to respond by forming a new morphology that differs from boulder‐free channels. The general approach presented here can be further expanded to explore the role of other hydrodynamic effects associated with large, rarely mobile boulders., Plain Language Summary: Large boulders are a significant feature in mountainous landscapes. Recent studies suggested that boulders residing in rivers interfere with the flow and sediment transport, forcing their geometry, specifically width and slope, to change. Our ability to understand and predict such changes is challenged by scarce field data and a general lack of models capable of explaining the processes underlying channel geometry adjustment in the presence of boulders. Here, we develop a theory and several models for the variation of channel width and slope as with channel boulder coverage. Our theory builds on the assumption that the geometry of boulder‐bed channels evolves to a new configuration to maintain steadiness of erosion rate and sediment transport. Predictions from the various models are tested against data from the steep Liwu River in Taiwan. These data show that width and slope increase with more boulders. We find that channel slope increases to overcome the greater resistance to sediment transport due to the boulders. In contrast, the scattered nature of the width data and the overall models inability to explain width variability likely reflect a longer adjustment period for width than for slope. This study demonstrates the important role of boulders in shaping landscapes., Key Points: We develop a theory for steady‐state reach‐scale channel morphology responding to large, rarely mobile boulders in bedrock rivers. Predictions of boulder‐bed channel width and slope are derived based on grade equilibrium and bedrock erosional balance. Theory is tested against new data from the Liwu River, Taiwan, showing steepening and widening with increasing boulder concentration., Israel Science Foundation http://dx.doi.org/10.13039/501100003977, NSF‐BSF, https://zenodo.org/record/6371224#.YjdBkOpByUk

We investigated four subaerial (paleo)lacustrine landforms at the north‐eastern shoreline of Schweriner See, north‐eastern Germany. These included two beach ridges, one subaerial nearshore bar and a silting up sequence located close to a fossil cliff, which marks the former maximum extent of Schweriner See. We used luminescence profiling with a SUERC portable OSL device (POSL) on all four sediment sequences in combination with sedimentological investigations such as grain size, loss‐on‐ignition and magnetic susceptibility to provide information on the various formations in a lacustrine depositional environment. The POSL reader was used on pre‐treated polymineral samples to gain an insight into luminescence distribution within the individual sediment sequences, but also among the four sequences. POSL proved valuable to understand depositional processes, which were not visible in lithology or sedimentological parameters. With somewhat larger uncertainty this method provides relative chronologies of the sediment sequences. Additionally, we carried out radiocarbon dating and full optical stimulated luminescence (OSL) dating to establish a chronological framework. OSL ages proved to be more reliable to date beach ridges in this setting than radiocarbon samples, which were severely influenced by sediment reworking. This combined approach of sedimentological analyses, luminescence profiling and absolute age determinations revealed details in depositional processes at Schweriner See which otherwise would have remained undetected. Furthermore, it helped to set these subaerial (paleo)lacustrine landforms in a chronological framework., Luminescence profiles were a tremendous help to a) identify additional breaks in sedimentological successions, b) interpret sediment structures in greater detail than it would have been possible from sedimentological and absolute age data (14C and OSL dating) alone and c) understand beach ridge formation at Schweriner See, where traditional sedimentological parameters showed no indications of depositional changes., German Research Foundation (DFG) http://dx.doi.org/10.13039/501100001659, Ministry of Agriculture and the Environment of the Federal State of Mecklenburg‐Western Pomerania, University of Greifswald/Federal State Mecklenburg‐Western Pomerania: Graduate Scholarship (Landesgraduiertenstipendium) http://dx.doi.org/10.13039/501100018934

Mesozoic submarine carbonate escarpments are erosional features that host box canyons, the formation of which had been attributed to seepage erosion in view of their similarity to subaerial box canyons. The latter had been cited as diagnostic of groundwater activity, although the efficacy of fluid seepage as an erosive agent in bedrock remains controversial. Here we use multibeam echosounder data from the Blake, Campeche, Malta and Florida Escarpments to demonstrate that box canyon formation is, in general, a significant process eroding carbonate escarpments. Numerical modeling based on parameters from the Florida Escarpment shows that box canyons can initiate and retrogressively evolve by fluid seeping via joints, which causes a reduction in rock strength due to fluid pressure and dissolution, resulting in periodic block failure at the canyon head. Box canyon elongation is promoted by an exponential distribution of joint density, an increase in joint density, joints oriented perpendicular and parallel to the escarpment, or an increase in the thickness of the flowing groundwater zone and slope gradient of the escarpment. The angularity of the canyon head decreases with a decrease in joint density and when joint density is uniform, whereas the canyon width is regulated by the extent of the joint set zone. Since the key factors contributing to box canyon formation along the Florida Escarpment appear to characterize the Blake, Campeche and Malta Escarpments, the groundwater model for box canyon formation should be applicable to these escarpments as well., Plain Language Summary: Submarine carbonate escarpments are cliffs of limestone and dolomite that form anomalously steep topography on the Earth's surface. Box canyons—wide canyons with steep walls and semi‐circular heads—are a common feature in carbonate escarpments and they have been associated with groundwater seepage. In this study, we use seafloor depth information from four carbonate escarpments to show that box canyon erosion is a key process driving their evolution. Numerical modeling, on the other hand, suggests that fluid seeping in conditions similar to those of the Florida Escarpment can result in box canyon formation via periodic failure of the canyon head. Since these conditions at the Florida Escarpment can also be found in other escarpments such as the Blake, Campeche and Malta Escarpments, box canyon formation by groundwater seepage is likely a widespread geological process. The location of box canyons may suggest where fluid is seeping along escarpments and where specialized biological communities may be located. Box canyon formation is unlikely to pose a risk to coastal communities and offshore infrastructure., Key Points: Box canyon formation is a significant erosive process across carbonate escarpments. Fluid seeping through joints can drive initiation and retrogressive evolution of box canyons via periodic block failure at the canyon head., EC, H2020, H2020 Priority Excellent Science, H2020 European Research Council (ERC) http://dx.doi.org/10.13039/100010663, EC, H2020, H2020 Priority Excellent Science, Marie Skłodowska‐Curie Actions, EC, FP7, FP7 Marie Curie Actions (MCA), Fulbright Association (FULBRIGHT) http://dx.doi.org/10.13039/100010629, David and Lucile Packard Foundation (PF) http://dx.doi.org/10.13039/100000008

Mixed sand‐ and gravel‐bed rivers record erosion, transport, and fining signals in their bedload size distributions. Thus, grain‐size data are imperative for studying these processes. However, collecting hundreds to thousands of pebble measurements in steep and dynamic high‐mountain river settings remains challenging. Using the recently published digital grain‐sizing algorithm PebbleCounts, we were able to survey seven large (≥ 1,000 m2) channel cross‐sections and measure thousands to tens‐of‐thousands of grains per survey along a 100‐km stretch of the trunk stream of the Toro Basin in Northwest Argentina. The study region traverses a steep topographic and environmental gradient on the eastern margin of the Central Andean Plateau. Careful counting and validation allows us to identify measurement errors and constrain percentile uncertainties using large sample sizes. In the coarse ≥2.5 cm fraction of bedload, only the uppermost size percentiles (≥95th) vary significantly downstream, whereas the 50th and 84th percentiles show less variability. We note a relation between increases in these upper percentiles and along‐channel junctions with large, steep tributaries. This signal is strongly influenced by lithology and geologic structures, and mixed with local hillslope input. In steep catchments like the Toro Basin, we suggest nonlinear relationships between geomorphic metrics and grain size, whereby the steepest parts of the landscape exert primary control on the upper grain‐size percentiles. Thus, average or median metrics that do not apply weights or thresholds to steeper topography may be less predictive of grain‐size distributions in such settings., Plain Language Summary: Rock fragments on hillsides are transported to rivers, eventually becoming pebbles, sand, and mud as they are carried downstream by flowing water. The initial size of the pebbles, the way the size changes downstream, and the overprinting of the sizes with new pebbles from other hills and tributaries all form a complex process that can be difficult to disentangle. Yet studying the size of the pebbles at a given stream location or in a sedimentary deposit can provide insights into the conditions of their transport in terms of local upstream patterns of erosion, tectonics, and climate. We show that just looking at the size of the large pebbles on a riverbed can be used to infer the sources of material, but, since there are fewer large pebbles, they require more measurements to quantify. This necessitates new methods for pebble measurement using modern image‐processing tools., Key Points: Complex grain‐size distributions in dynamic mountain rivers can be computed via thousands of measurements from PebbleCounts. Many measurements allow robust estimation of higher percentiles and we observe the most significant changes in the ≥95th percentile. Downstream grain‐size variation is nonlinearly related to variations in topographic steepness and lithology., Deutsches Zentrum für Luft‐ und Raumfahrt (DLR) http://dx.doi.org/10.13039/501100002946, Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659, Bundesministerium für Bildung und Forschung (BMBF) http://dx.doi.org/10.13039/501100002347, Brandenburger Staatsministerium für Wissenschaft, Forschung und Kultur (MWFK) http://dx.doi.org/10.13039/501100004581, https://zenodo.org/record/5089789

Much of contemporary landslide research is concerned with predicting and mapping susceptibility to slope failure. Many studies rely on generalised linear models with environmental predictors that are trained with data collected from within and outside of the margins of mapped landslides. Whether and how the performance of these models depends on sample size, location, or time remains largely untested. We address this question by exploring the sensitivity of a multivariate logistic regression—one of the most widely used susceptibility models—to data sampled from different portions of landslides in two independent inventories (i.e. a historic and a multi-temporal) covering parts of the eastern rim of the Fergana Basin, Kyrgyzstan. We find that considering only areas on lower parts of landslides, and hence most likely their deposits, can improve the model performance by >10% over the reference case that uses the entire landslide areas, especially for landslides of intermediate size. Hence, using landslide toe areas may suffice for this particular model and come in useful where landslide scars are vague or hidden in this part of Central Asia. The model performance marginally varied after progressively updating and adding more landslides data through time. We conclude that landslide susceptibility estimates for the study area remain largely insensitive to changes in data over about a decade. Spatial or temporal stratified sampling contributes only minor variations to model performance. Our findings call for more extensive testing of the concept of dynamic susceptibility and its interpretation in data-driven models, especially within the broader framework of landslide risk assessment under environmental and land-use change., Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347

This article attempts to reconstruct the causes and consequences of the 2014 glacial lake outburst flood (GLOF) event in Gya, Ladakh. We analyse the evolution of the Gya glacial lake using a high temporal and high spatial resolution remote sensing approach. In order to frame the case study in a larger picture, we produce a comprehensive inventory of glacial lakes for the entire Trans-Himalayan region of Ladakh. Changes in the extent and number of glacial lakes have been detected for the years 1969, 1993, 2000/02 and 2018 in order to assess the potential risk of future GLOFs in the region. The remote sensing approach was supported by field surveys between 2014 and 2019. The case study of the Gya GLOF illustrates the problem of potentially hazardous lakes being overlooked in inventories. The broader analysis of the Ladakh region and in-depth analysis of one GLOF lead us to propose an integrated approach for detecting undocumented GLOFs. This article demonstrates the necessity for using multiple methods to ensure robustness of risk assessment. The improved understanding can lead to a more accurate evaluation of exposure to cryosphere hazards and identification of alternative mechanisms and spatial patterns of GLOFs in the Himalaya., Universität Heidelberg http://dx.doi.org/10.13039/501100001661

After almost 200 years of exposure, the monuments of General Scharnhorst and Bülow have been analysed by means of ultrasound. Both sculptures are made of Carrara marble, both sculptures have been exposed to the same environmental influences and both sculptures are, based on the results of the ultrasonic measurements, in alarming conditions. This statement can be made because of the data of three different measurement investigations within the last 12 years. In this short exposure time, the already low velocities have been reduced by 16.2% and 14.7%. The very low average velocity of 2.8 km/s for the sculpture of General Bülow and a slightly higher average velocity of 3.2 km/s for the Scharnhorst sculpture indicate that both sculptures are in a poor condition, even though a protective winter shelter has been used since 2004. Comparing tomographic velocity measurements performed in 2006 with the measurements made in 2018 was possible and showed that even areas with a thickness up to 90 cm show alarming low ultrasonic velocities down to 2.6 km/s. Even if the circumstances for both sculptures have been the same, they differ in their weathering state. The careful and transparent documentation of all measurements was in this context the most important aspect for the comparative studies. Irregularities in their weathering behaviour of the two statues can be distinguished, allowing an in-depth analysis of the deterioration of the marble., Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347

Ausgehend von der Überlegung, daß sich unterschiedliche Faziesbedingungen nicht nur in sedimentologischen Merkmalen, sondern auch in ingenieurgeologischen Eigenschaften und damit im bodenmechanischen Verhalten widerspiegeln müssen, wird für die Sedimente des Küstenholozäns ein ingenieurgeologisches Ordnungsprinzip auf der Basis bodenmechanischer Kennziffern entwickelt. Für drei Gebiete der südlichen Nordsee (Emden, Wilhelmshaven, Bremerhaven) wird bodenmechanisches Datenmaterial aus eigenen Untersuchungen und aus zahlreichen Baugrundgutachten in das gültige geologisch lithologische Ordnungsschema (BARCKHAUSEN et a l . 1977) eingepaßt und dann auf seine ingenieurgeologische Gruppenstruktur hin untersucht. Von insgesamt 1200 lithofaziell zugeordneten Proben aus dem Untersuchungsschwerpunkt Emden-Krummhörn und den Vergleichsgebieten Wilhelmshaven-Voslapp und Bremerhaven liegen Daten über Korngrößenverteilung, Glühverlust, Porenziffer, Wassergehalt, Wichte, Konsistenzgrenzen, Aktivität, Kohäsion, Reibungswinkel, c -Festigkeit und Steifemoduln von vier Laststufen vor, die mit multivariaten statistischen Methoden gruppiert und korreliert werden…, thesis, DFG, SUB Göttingen