Sedimentary coastal cliffs of Normandy: Modalities and quantification of retreat
Stéphane Costa
(1)
,
Olivier Maquaire
(1)
,
Pauline Letortu
(1)
,
Guillaume Thirard
(1)
,
Vincent Compain
(1)
,
Thomas Roulland
(1)
,
Mohand Medjkane
(1)
,
Robert Davidson
(1)
,
Kevin Graff
(1)
,
Candide Lissak
(1)
,
Christophe Delacourt
(2)
,
Timothée Duguet
(3)
,
Cyrille Fauchard
(4)
,
Raphaël Antoine
(4)
Stéphane Costa
- Fonction : Auteur
- PersonId : 6083
- IdHAL : stephane-costa
- IdRef : 096705426
Olivier Maquaire
- Fonction : Auteur
- PersonId : 6068
- IdHAL : olivier-maquaire
- IdRef : 03137221X
Pauline Letortu
- Fonction : Auteur
- PersonId : 3966
- IdHAL : pauline-letortu
- ORCID : 0000-0003-4035-3866
- IdRef : 129342238
Guillaume Thirard
- Fonction : Auteur
- PersonId : 1127132
- IdRef : 151191190
Thomas Roulland
- Fonction : Auteur
- PersonId : 1024312
Mohand Medjkane
- Fonction : Auteur
- PersonId : 177475
- IdHAL : mohand-medjkane
- ORCID : 0000-0001-9691-1797
- IdRef : 156671247
Robert Davidson
- Fonction : Auteur
- PersonId : 5720
- IdHAL : robert-davidson
- ORCID : 0000-0003-1911-705X
- IdRef : 116302283
Candide Lissak
- Fonction : Auteur
- PersonId : 7488
- IdHAL : candide-lissak
- IdRef : 167584804
Christophe Delacourt
- Fonction : Auteur
- PersonId : 1157115
- ORCID : 0000-0003-2484-1464
- IdRef : 080257763
Cyrille Fauchard
- Fonction : Auteur
- PersonId : 175176
- IdHAL : cyrille-fauchard
- ORCID : 0000-0002-9756-6179
- IdRef : 084642017
Raphaël Antoine
- Fonction : Auteur
- PersonId : 734799
- IdHAL : raphael-antoine
- ORCID : 0000-0002-0625-9713
- IdRef : 144523698
Résumé
This paper examines the spatial and temporal variations of cliff retreat rates over multi-temporal data of the Normandy cliffs. Data are derived from historical maps and aerial photographs and from recent lasergrammetry and photogrammetry monitoring. The diachronic analysis of all these data gives retreat rates of -0.1 to -0.5 m/yr. in line with the international literature. The spatial variations of the cliff retreat rates, at the Normandy scale, can be explained by geological structure, especially at the cliff foot, but also by the influence of cliff collapses or anthropogenic obstacles that disrupt the longshore drift. Multi-temporal data shows that the evolution of the cliffs occurs on scales from 10 to 70 years according to the lithology. The high resolution and frequency monitoring also provide information about the factors responsible for triggering gravitational landslides (rockfalls, slides, debris falls). The study proposes a regional warning threshold for the cliff characterized by landslides, under the dominating influence of rainfall and groundwater level evolution. In this respect the monitoring is inconclusive for chalk and limestone cliffs, because the origin of evolutions is more multifactorial (combination of more continental and marine processes).
Domaines
GéographieFormat du dépôt | Fichier |
---|---|
Type de dépôt | Article dans une revue |
Titre |
en
Sedimentary coastal cliffs of Normandy: Modalities and quantification of retreat
|
Résumé |
en
This paper examines the spatial and temporal variations of cliff retreat rates over multi-temporal data of the Normandy cliffs. Data are derived from historical maps and aerial photographs and from recent lasergrammetry and photogrammetry monitoring. The diachronic analysis of all these data gives retreat rates of -0.1 to -0.5 m/yr. in line with the international literature. The spatial variations of the cliff retreat rates, at the Normandy scale, can be explained by geological structure, especially at the cliff foot, but also by the influence of cliff collapses or anthropogenic obstacles that disrupt the longshore drift. Multi-temporal data shows that the evolution of the cliffs occurs on scales from 10 to 70 years according to the lithology. The high resolution and frequency monitoring also provide information about the factors responsible for triggering gravitational landslides (rockfalls, slides, debris falls). The study proposes a regional warning threshold for the cliff characterized by landslides, under the dominating influence of rainfall and groundwater level evolution. In this respect the monitoring is inconclusive for chalk and limestone cliffs, because the origin of evolutions is more multifactorial (combination of more continental and marine processes).
|
Auteur(s) |
Stéphane Costa
1
, Olivier Maquaire
1
, Pauline Letortu
1
, Guillaume Thirard
1
, Vincent Compain
1
, Thomas Roulland
1
, Mohand Medjkane
1
, Robert Davidson
1
, Kevin Graff
1
, Candide Lissak
1
, Christophe Delacourt
2
, Timothée Duguet
3
, Cyrille Fauchard
4
, Raphaël Antoine
4
1
LETG - Caen -
Littoral, Environnement, Télédétection, Géomatique
( 929 )
- Esplanade de la Paix, CS 14032, 14032 Caen cedex 5
- France
2
IUEM -
Institut Universitaire Européen de la Mer
( 413764 )
- IUEM Technopôle Brest-Iroise - rue Dumont d'Urville - 29280 Plouzané
- France
3
LOMC -
Laboratoire Ondes et Milieux Complexes
( 56485 )
- 53 rue de Prony
76058 Le Havre Cedex
- France
4
ENDSUM -
Evaluation non destructive des structures et des matériaux
( 1170582 )
- France
|
Langue du document |
Anglais
|
Nom de la revue |
|
Vulgarisation |
Non
|
Comité de lecture |
Oui
|
Audience |
Internationale
|
Date de publication |
2019-12-11
|
Volume |
88
|
Numéro |
sp1
|
Page/Identifiant |
46-60
|
Commentaire |
https://doi.org/10.2112/SI88-005.1.
|
Domaine(s) |
|
Projet(s) ANR |
|
Mots-clés |
en
landslide, retreat rate, lasergrammetry, photogrammetry, Coastal cliff
|
DOI | 10.2112/SI88-005.1 |
Origine :
Fichiers produits par l'(les) auteur(s)
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