L
T
Last name: LEBOURG
First name: Thomas
International audience
Les glissements de terrain de grande ampleur (ʋ > 106m3) sont des objets géomorphologiques complexes dont la cinématique propose des contraintes temporelles à mi-chemin entre les temps géologiques et les temps Humains. Le principal défi scientifique repose sur la compréhension des temps de récurrences et d'accélération des masses, et les...
The first erosional front of the south‐eastern Alps has been affected by several deep‐seated landslides. The movements affected a Jurassic limestone sequence underlain by an upper Trias unit (Keuper) mainly composed of marl and clays. Horst‐ and graben‐like structures, newly formed gravitational faults, outflow and other field evidence suggest...
International audience
The area of risk management in geo-hazards is fairly complex due to extreme and unpredictable climatic events. Studies of natural hazard, risk and vulnerability have increased significantly in the last 20-25 years leading to a marked improvements in our understanding of core issues at the heart of these concepts. Emergence of vulnerability is...
The research work we have been doing in the laboratory has allowed us for more than a decade to map and study tens of large landslides in the southern part of the Alps. During this cartographic research, we identified a new zone which revealed the presence of a landslide of incomparable size and which uses a triggering process linked to the...
The morphology of rocky coastlines is the expression of the interaction between external forcings and the intrinsic rock mass properties, leading to a specific erosional response. Among these rock mass properties the contribution of structural discontinuities is still poorly understood. Nevertheless, recent studies suggest that geological...
Terrestrial laser scanners (TLS) are well known for providing an efficient means to monitor coastal cliff erosion. Cliffs along micro-tidal coasts, however, have often escaped quantification because the narrow or absent coastal platforms do not offer stable and embracing vantage points. To circumvent this issue, mobile laser scanning surveys...
ABSTRACT In the past decade, passive seismic methods have shown the possibility to detect significant changes in surface wave velocity up to several days prior to landslide failure, even with sensors located outside the unstable zone. Electrical resistivity tomography has also long been used to monitor hydrological changes in landslides....
On October 2, 2020, the Alpes-Maritimes was hit by precipitations of tremendous intensity, particularly in the inlands of Nice in the Tinée, Vésubie and Roya valleys, in the foothills of the Mercantour massif.The fury of this rainfall is the result of a well-known phenomenon of a Mediterranean event: a convective multi-cell cluster with...
The objective of this work is to document the deformation pattern of the deep-seated La Clapière landslide for the period 2007–2010 from the combination of L-band synthetic aperture radar (SAR) interferograms, ground-based total station measurements and identification of the slope geomorphological structures. The interferograms are calculated...
La mise au point de système d'alerte pour les glissements de terrain reste encore à l'heure actuelle un défi scientifique, logistique, technique et juridique. Les principaux freins à son développement sont l'accessibilité au site d'étude, la complexité lithologique, la variabilité des mécanismes de rupture dans les massifs et la gestion des...
A hydrogeophysical study was carried out by a water controlled injection within a landslide situated on an active part of the La Clapière landslide foot (Alpes Maritimes, France). Coupling of both real-time geophysical and hydrological follow ups allowed the representation and quantification of the surface water drainage in space and time...
International audience
International audience
Geophysical surveys were conducted on the very unstable front part of the La Clapière landslide in the French Alps (Alpes Maritimes). The electrical resistivity survey was carried out to obtain, for the first time on this deep-seated landslide, 3D information on the slipping surface and the vertical drained faults. Moreover, we planned to...
The geology of the "Vence" landslide (0.8 million m3, south-eastern France) explains the complex hydrology of the site which plays a key role in the destabilization of the slope (water circulation within the sliding mass, fluid exchanges between superficial layers and deep karstic aquifer through faults). To understand fluid circulations within...
This paper highlights potential complications that may arise while using in situ produced 10 Be to date exposure or burial events using diagenetic silica (chert). The initiation and evolution of large gravitational collapses in sedimentary rocks were constrained using cosmic ray exposure dating. Because these col- lapses occurred in a...
Improving the resilience of territories to landslides is a rising need for security managers in a context of climate change, with the increase in frequency and intensity of extreme events. The French Alpes-Maritimes department has experienced numerous episodes of intense rainfall over the last twenty years, with some particularly notable in...
Fluidisation occurring in clay-rich landslides poses serious threats to populations and infrastructures and has been the subject of numerous studies to apprehend its rheological origin. In parallel, noninvasive geophysical techniques on landslides have known considerable development as a means to approach in-situ geotechnical parameters. This...
La Crise messinienne et sa cicatrisation se sont déroulées en plusieurs étapes depuisl'incision des cours d'eau jusqu'au remblaiement sédimentaire rapide et progradant decanyons en Gilbert deltas. G. Clauzon (1996) a pu définir quatre niveaux-repèresmorphologiques et stratigraphiques qu'il proposait d'utiliser pour quantifier les...
Le bassin versant de la Roya présente une partie amont située dans les Alpes-Maritimes, et un exutoire à Vintimille (Italie). Le caractère torrentiel du fleuve et l'occurrence d'intenses crues éclair, typiques du régime méditerranéen, en font un système fluvial particulièrement actif et complexe du point de vue hydromorphologique. L'étude...