Spatial analysis of coastal chalk cliff falls in Upper Normandy (France) from Veules-les-Roses to Le Treport (2002-2009)

Abstract : Coastal chalk cliff falls in Upper Normandy (France) are frequent and have specific spatial and temporal distributions. From 2002 to 2009, the ESTRAN organization (Scientific and Technical Space of Aquatic Resources and Navigation) conducted a weekly inventory of 331 cliff falls (location, volume, and date) between Veules-les-Roses and Le Treport (37.5 km). An amount of 331 falls was counted (date, location, measures of fall deposit). This database is remarkable because of the duration and high frequency of field surveys. The geographical and spatial statistics (locational analysis) methods used in this study aim to determine and understand the spatial and temporal distributions of coastal chalk cliff falls. Exhaustive cartography of such falls thus highlights the cap d'Ailly sector as being the most sensitive to an erosive dynamic along the coast from Veules-les-Roses to Le Treport. Furthermore, this cartography stresses many types of fall kinematics. This can be partly explained by lithological characteristics may predispose mass and particle movements. Using the combination of centrographic statistics, Ripley's K-function, Besag's L-function and kernel density, we have identified: (1) high cliff fall polarization at cap d'Ailly; (2) organization scales of fall locations per water year; (3) areas of massive and numerous falls (fall hazard areas). This information is essential for a better understanding of the working of the studied area and also for the set up of risk prevention tools.
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Submitted on : Sunday, October 5, 2014 - 11:02:16 AM
Last modification on : Tuesday, August 27, 2019 - 11:02:09 AM

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Pauline Letortu, Stéphane Costa, Emmanuel Bonnet. Spatial analysis of coastal chalk cliff falls in Upper Normandy (France) from Veules-les-Roses to Le Treport (2002-2009). Revue Internationale de Géomatique, Lavoisier, 2014, 24 (3), pp.335-354. ⟨10.3166/rig.24.335-354⟩. ⟨hal-01071427⟩

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