References of "Demoulin, Alain"
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See detailA susceptibility-based rainfall threshold approach for landslide occurrence
Monsieurs, Elise ULiege; Dewitte, Olivier; Demoulin, Alain ULiege

in Natural Hazards and Earth System Sciences (2019), 19

Rainfall threshold determination is a pressing issue in the landslide scientific community. While major improvements have been made towards more reproducible techniques for the identification of ... [more ▼]

Rainfall threshold determination is a pressing issue in the landslide scientific community. While major improvements have been made towards more reproducible techniques for the identification of triggering conditions for landsliding, the now well-established rainfall intensity or event-duration thresholds for landsliding suffer from several limitations. Here, we propose a new approach of the frequentist method for threshold definition based on satellite-derived antecedent rainfall estimates directly coupled with landslide susceptibility data. Adopting a bootstrap statistical technique for the identification of threshold uncertainties at different exceedance probability levels, it results in thresholds expressed as AR = (α±Δα)⋅S(β±Δβ), where AR is antecedent rainfall (mm), S is landslide susceptibility, α and β are scaling parameters, and Δα and Δβ are their uncertainties. The main improvements of this approach consist in (1) using spatially continuous satellite rainfall data, (2) giving equal weight to rainfall characteristics and ground susceptibility factors in the definition of spatially varying rainfall thresholds, (3) proposing an exponential antecedent rainfall function that involves past daily rainfall in the exponent to account for the different lasting effect of large versus small rainfall, (4) quantitatively exploiting the lower parts of the cloud of data points, most meaningful for threshold estimation, and (5) merging the uncertainty on landslide date with the fit uncertainty in a single error estimation. We apply our approach in the western branch of the East African Rift based on landslides that occurred between 2001 and 2018, satellite rainfall estimates from the Tropical Rainfall Measurement Mission Multi-satellite Precipitation Analysis (TMPA 3B42 RT), and the continental-scale map of landslide susceptibility of Broeckx et al. (2018) and provide the first regional rainfall thresholds for landsliding in tropical Africa. [less ▲]

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See detailAdopting rainfall threshold analysis for landslides in Central Africa using satellite rainfall estimates
Monsieurs, Elise ULiege; Dewitte, Olivier; Kirschbaum, Dalia et al

Poster (2018, December 11)

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See detailEvaluating TMPA Rainfall over the Sparsely Gauged East African Rift
Monsieurs, Elise ULiege; Kirschbaum, Dalia; Tan, Jackson et al

in Journal of Hydrometeorology (2018), 19(9),

Accurate precipitation data are fundamental for understanding and mitigating the disastrous effects of many natural hazards in mountainous areas. Floods and landslides, in particular, are potentially ... [more ▼]

Accurate precipitation data are fundamental for understanding and mitigating the disastrous effects of many natural hazards in mountainous areas. Floods and landslides, in particular, are potentially deadly events that can be mitigated with advanced warning, but accurate forecasts require timely estimation of precipitation, which is problematic in regions such as tropical Africa with limited gauge measurements. Satellite rainfall estimates (SREs) are of great value in such areas, but rigorous validation is required to identify the uncertainties linked to SREs for hazard applications. This paper presents results of an unprecedented record of gauge data in the western branch of the East African Rift, with temporal resolutions ranging from 30 min to 24 h and records from 1998 to 2018. These data were used to validate the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) research version and near-real-time products for 3-hourly, daily, and monthly rainfall accumulations, over multiple spatial scales. Results indicate that there are at least two factors that led to the underestimation of TMPA at the regional level: complex topography and high rainfall intensities. The TMPA near-real-time product shows overall stronger rainfall underestimations but lower absolute errors and a better performance at higher rainfall intensities compared to the research version. We found area-averaged TMPA rainfall estimates relatively more suitable in order to move toward regional hazard assessment, compared to data from scarcely distributed gauges with limited representativeness in the context of high rainfall variability. [less ▲]

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See detailSeismotectonic activity in East Belgium: relevance of a major scarp and two associated landslides in the region of Malmedy
Mreyen, Anne-Sophie ULiege; Demoulin, Alain ULiege; Havenith, Hans-Balder ULiege

in Geologica Belgica (2018), 21(3-4), 101-110

Geomorphological markers such as scarps, river diversions and slope failures can be used as proxy indicators for the seismotectonic activity of a region. This study concentrates on the Malmedy-Bévercé ... [more ▼]

Geomorphological markers such as scarps, river diversions and slope failures can be used as proxy indicators for the seismotectonic activity of a region. This study concentrates on the Malmedy-Bévercé area, E-Belgium, where formerly unknown geomorphological features have been recently discovered in the frame of a new regional geological mapping campaign. The area is characterised by gentle to locally very steep slopes along the Warche valley crossing the Stavelot Massif and the Malmedy Graben. Coupled with a LiDAR-DEM and UAV imagery analysis, field mapping has revealed a steep scarp extending near two landslides on the southern hillslopes of the Warche valley at Bévercé. These slope failures developed in the Permian conglomerates of the Malmedy Formation (also known as the Poudingue de Malmedy), which represent the infill of the Malmedy Graben. Roughly perpendicular to the graben axis, the scarp has a N330°E orientation similar to that of the seismotectonically active Hockai Fault Zone that crosses the Malmedy region in this area. In this paper, we present the geological and geomorphological context of the Bévercé scarp and of the largest landslide. Furthermore, we demonstrate the results of a geophysical reconnaissance survey of the structures (seismic refraction and electrical resistivity profiling). The geophysical results highlight a vertical displacement of the seismic layers and laterally changing electrical properties across the scarp, with very low resistivity values in its middle part. A low resistivity zone in the subsurface can also be found within the larger landslide, right in the prolongation of the scarp. All these observations hint at the presence of a major, probably seismically active, fault belonging to the eastern border of the Hockai Fault Zone. [less ▲]

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See detailLandslide inventory for hazard assessment in a data- poor context: a regional-scale approach in a tropical African environment
Monsieurs, Elise ULiege; Jacobs, Liesbet; Michellier, Caroline et al

in Landslides (2018)

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See detailPlio-Quaternary incision rates in the Meuse catchment vs long-term uplift rates of the Ardennes (E Belgium): new insights from 26Al/10Be burial dating of in cave-deposited alluvium
Rixhon, Gilles; Bourlès, Didier; Braucher, Régis et al

Conference (2018, April 09)

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See detailApplying Pattern Oriented Sampling in current fieldwork practice to enable more effective model evaluation in fluvial landscape evolution research
Briant, R. M.; Cohen, K. M.; Cordier, Stéphane et al

in Earth Surface Processes and Landforms (2018), 43

Field geologists and geomorphologists are increasingly looking to numerical modelling to understand landscape change over time, particularly in river catchments. The application of landscape evolution ... [more ▼]

Field geologists and geomorphologists are increasingly looking to numerical modelling to understand landscape change over time, particularly in river catchments. The application of landscape evolution models (LEMs) started with abstract research questions in synthetic landscapes. Now, however, studies using LEMs on real-world catchments are becoming increasingly common. This development has philosophical implications for model specification and evaluation using geological and geomorphological data, besides practical implications for fieldwork targets and strategy. The type of data produced to drive and constrain LEM simulations has very little in common with that used to calibrate and validate models operating over shorter timescales, making a new approach necessary. Here we argue that catchment fieldwork and LEM studies are best synchronized by complementing the Pattern Oriented Modelling (POM) approach of most fluvial LEMs with Pattern Oriented Sampling (POS) fieldwork approaches. POS can embrace a wide range of field data types, without overly increasing the burden of data collection. In our approach, both POM output and POS field data for a specific catchment are used to quantify key characteristics of a catchment. These are then compared to provide an evaluation of the performance of the model. Early identification of these key characteristics should be undertaken to drive focused POS data collection and POM model specification. Once models are evaluated using this POM/POS approach, conclusions drawn from LEM studies can be used with greater confidence to improve understanding of landscape change. © 2018 John Wiley & Sons, Ltd. [less ▲]

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See detailGeomorphic response to active tectonics: Numerical and field-based approaches
Demoulin, Alain ULiege; Schiattarella, M.; Pedersen, V. K.

in Earth Surface Processes and Landforms (2018), 43

[No abstract available]

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See detailThe climate of Belgium and Luxembourg
Erpicum, Michel ULiege; Nouri, Myriem ULiege; Demoulin, Alain ULiege

in Demoulin, Alain (Ed.) Landscapes and landforms of Belgium and Luxembourg (2018)

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See detailCharacteristics and frequency of large submarine landslides at the western tip of the Gulf of Corinth
Beckers, Arnaud; Hubert, Aurelia ULiege; Beck, Christian et al

in Natural Hazards and Earth System Sciences (2018)

Coastal and submarine landslides are frequent at the western tip of the Gulf of Corinth, where small to medium failure events (106–107 m3/ occur on average every 30–50 years. These landslides trigger ... [more ▼]

Coastal and submarine landslides are frequent at the western tip of the Gulf of Corinth, where small to medium failure events (106–107 m3/ occur on average every 30–50 years. These landslides trigger tsunamis and consequently represent a significant hazard. We use here a dense grid of high-resolution seismic profiles to realize an inventory of the large mass transport deposits (MTDs) that result from these submarine landslides. Six large mass wasting events are identified, and their associated deposits locally represent 30% of the sedimentation since 130 ka in the main western basin. In the case of a large MTD of 1 km3 volume, the simultaneous occurrence of different slope failures is inferred and suggests an earthquake triggering. However, the overall temporal distribution of MTDs would result from the time-dependent evolution of pre-conditioning factors rather than from the recurrence of external triggers. Two likely main pre-conditioning factors are (1) the reloading time of slopes, which varied with the sedimentation rate, and (2) dramatic changes in water depth and water circulation that occurred 10–12 ka ago during the last post-glacial transgression. Such sliding events likely generated large tsunami waves in the whole Gulf of Corinth, possibly larger than those reported in historical sources considering the observed volume of the MTDs. [less ▲]

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See detailLandslides in Belgium: two case studies in the Flemish Ardennes and the Pays de Herve
Dewitte, O.; Van den Eeckhaut, M.; Poesen, J. et al

in Landscapes and landforms of Belgium and Luxembourg (2018)

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See detailThe Flemish Valley: Response of the Scheldt drainage system to climatic and glacio-eustatic oscillations
Heyse, I.; Demoulin, Alain ULiege

in Demoulin, Alain (Ed.) Landscapes and landforms of Belgium and Luxembourg (2018)

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See detailMorphotectonics and past large earthquakes in eastern Belgium
Vanneste, K.; Camelbeeck, T.; Verbeeck, K. et al

in Demoulin, Alain (Ed.) Landscapes and landforms of Belgium and Luxembourg (2018)

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See detailThe picturesque Ardennian valleys: Plio-Quaternary incision of the drainage system in the uplifting Ardenne
Rixhon, Gilles; Demoulin, Alain ULiege

in Demoulin, Alain (Ed.) Landscapes and landforms of Belgium and Luxembourg (2018)

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See detailThe periglacial ramparted depressions of the Hautes Fagnes Plateau: traces of Late Weichselian lithalsas
Demoulin, Alain ULiege; Houbrechts, Geoffrey ULiege; Juvigné, Etienne ULiege

in Demoulin, Alain (Ed.) Landscapes and landforms of Belgium and Luxembourg (2018)

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See detailA unique boulder-bed reach of the Amblève River, Ardenne, at Fonds de Quarreux: Modes of boulder transport
Houbrechts, Geoffrey ULiege; Petit, François ULiege; Van Campenhout, Jean ULiege et al

in Demoulin, Alain (Ed.) Landscapes and landforms of Belgium and Luxembourg (2018)

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See detailErosion surfaces in the Ardenne-Oesling and their associated kaolinic weathering mantle
Demoulin, Alain ULiege; Barbier, F.; Deconinck, A. et al

in Landscapes and landforms of Belgium and Luxembourg (2018)

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See detailMorphogenic setting and diversity of processes and landforms: The geomorphological regions of Belgium
Demoulin, Alain ULiege

in Demoulin, Alain (Ed.) Landscapes and landforms of Belgium and Luxembourg (2018)

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