The role of groundwater in cliff instability: an example at Cape Blanc‐Nez (Pas‐de‐Calais, France)

Pierre, Guillaume; Lahousse, Philippe

doi:10.1002/esp.1229

Cited by 46 publications

(24 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, few studies have treated this coastline as a holistic unit (e.g. Halcrow, 1997) and investigated rates and modes of failure along the continuous section as in the approach adopted by Pierre and Lahousse (2006) and Pierre (2006) for cliff sections in northern France. Such an approach is required as rates of cliff retreat along the coast vary considerably, but details of the specific changes that are local to each Chine are required to define their respective stabilities.…”

Section: Cliff Recession Ratesmentioning

confidence: 99%

An empirical–conceptual gully evolution model for channelled sea cliffs

Leyland

Darby

2008

Geomorphology

View full text Add to dashboard Cite

Incised coastal channels are a specific form of incised channel that are found in locations where stream channels flowing to cliffed coasts have the excess energy required to cut down through the cliff to reach the outlet water body. The southern coast of the Isle of Wight, southern England, comprises soft cliffs that vary in height between 15 and 100 m and which are retreating at rates ≤ 1.5 m a − 1 , due to a combination of wave erosion and landslides. In several locations, river channels have cut through the cliffs to create deeply (≤45 m) incised gullies, known locally as 'Chines'. The Chines are unusual in that their formation is associated with dynamic shoreline encroachment during a period of rising sea-level, whereas existing models of incised channel evolution emphasise the significance of base level lowering. This paper develops a conceptual model of Chine evolution by applying space for time substitution methods using empirical data gathered from Chine channel surveys and remotely sensed data. The model identifies a sequence of evolutionary stages, which are classified based on a suite of morphometric indices and associated processes. The extent to which individual Chines are in a state of growth or decay is estimated by determining the relative rates of shoreline retreat and knickpoint recession, the former via analysis of historical aerial images and the latter through the use of a stream power erosion model.

show abstract

Section: Cliff Recession Ratesmentioning

confidence: 99%

An empirical–conceptual gully evolution model for channelled sea cliffs

Leyland

Darby

2008

Geomorphology

View full text Add to dashboard Cite

show abstract

“…A. Coe (jcoe@usgs.gov) Jaboyedoff et al, 2004). Discontinuities also affect the flow of water (Freeze and Cherry, 1979), which can adversely impact slope stability (Pierre and Lahousse, 2006).…”

Section: Introductionmentioning

confidence: 99%

Influence of tectonic folding on rockfall susceptibility, American Fork Canyon, Utah, USA

Coe

Harp

2007

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. We examine rockfall susceptibility of folded strata in the Sevier fold-thrust belt exposed in American Fork Canyon in north-central Utah. Large-scale geologic mapping, talus production data, rock-mass-quality measurements, and historical rockfall data indicate that rockfall susceptibility is correlated with limb dip and curvature of the folded, cliff-forming Mississippian limestones. On fold limbs, rockfall susceptibility increases as dip increases. This relation is controlled by several factors, including an increase in adverse dip conditions and apertures of discontinuities, and shearing by flexural slip during folding that has reduced the friction angles of discontinuities by smoothing surface asperities. Susceptibility is greater in fold hinge zones than on adjacent limbs primarily because there are greater numbers of discontinuities in hinge zones. We speculate that susceptibility increases in hinge zones as fold curvature becomes tighter.

show abstract

“…Some other coastal areas of the Channel are made of sedimentary layers of marls, sands and overlying chalk. Along these coastal segments, slope movements are slow and regularly reactivated, as observed at Villerville (Lower Normandy, France) (Flageollet and Helluin, 1987;Maquaire, 1990), in Upper Normandy at Sainte-Adresse (Sinelle, 1989) jeudi 9 juin 2011 and in northern Boulonnais (Pas-de-Calais, France) (Pierre, 2006;Pierre and Lahousse, 2006). In the United Kingdom, slow slope movements have also been reported along coastal cliffs having similar lithologies in South Kent at Hythe (Bromhead et al, 1998), at Folkestone Warren (Hutchinson, 1969;Bromhead and Ibsen, 2007), and along the South coast of the Isle of Wight at Ventnor and Bonchurch (Hutchinson, 1991;Hutchinson et al, 1991;Palmer et al, 2007a;Moore et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Numerical and physical modelling of coastal cliff retreat processes between La Hève and Antifer capes, Normandy (NW France)

Cossec

Duperret

Vendeville³

et al. 2011

Tectonophysics

View full text Add to dashboard Cite

The study area is located along the French eastern Channel coastline, in Upper Normandy, between the La Hève and Antifer capes. The sedimentary series dip North-Eastward by 0.7° and comprise clay layers (Kimmeridgian and Albian clays) located at varying vertical elevation along the cliff (about 90m high). This coastal cliff section is undergoing slow gravitational deformation, assumed to take place along the clay layers. Using numerical and experimental models, we investigated the role of clay layers, acting as potential detachment layers, on the development of gravitational instabilities. In order to properly design our models, we characterized the rock mechanical parameters using triaxial shear tests on in-situ samples dated from Kimmeridgian to Cenomanian. We ran a series of numerical simulations using a finite-element code applied to 2-D cliff cross section having varying lithological and mechanical layering. Under the sole effect of gravity forces, the plastic strains are mainly localised along the two clay layers, and the predicted displacements evidence a seaward sliding of the cliff. We further investigated gravitational deformation in the cliff using experimental models subjected to high pore-fluid pressure using by injecting compressed air at the base of the model. The presence of fluid overpressure can trigger spontaneous dismemberment of a cliff that would otherwise remain stable.The region of the model located near the initial cliff spread seaward, which generated a set of normal -2-faults that propagated landward and create a frontal toe bulge. We modelled a more complex initial geometry closer that observed in the field by simulating the northward progressive deepening of a potential décollement (the Gault clay). In the segment of the model where the potential décollement layer lay above or at the cliff's base, the absence of frontal buttress allowed for a large part of the cliff to slide seaward. The compressional toe of the deformed wedge progressively grew, thus acting as a buttress preventing further sliding. Removal of this toe by erosion lead to renewed gliding. Going northward, the vertical position of the potential décollement layer deepened, below the base of the cliff. There, the chalky shore platform acts as a buttress and the cliff deformation and seaward translation stops. Results lead us to hypothesize that cliff retreat would be faster where the potential décollement layer is located higher in the cliff along the southern segment. Therefore, the overall cliff trend would progressively rotate counterclockwise with ongoing deformation and erosion. This modelling works illustrates why the coastline trend changes drastically between the north (N60E) and the south segment (N25E). This progressive coastline re-orientation through time is confirmed by the fan-shape morphology of the bathymetry offshore the southern segment whereas the northern one presents a slight and regular slope.

show abstract

The role of groundwater in cliff instability: an example at Cape Blanc‐Nez (Pas‐de‐Calais, France)

Cited by 46 publications

References 28 publications

An empirical–conceptual gully evolution model for channelled sea cliffs

An empirical–conceptual gully evolution model for channelled sea cliffs

Influence of tectonic folding on rockfall susceptibility, American Fork Canyon, Utah, USA

Numerical and physical modelling of coastal cliff retreat processes between La Hève and Antifer capes, Normandy (NW France)

Contact Info

Product

Resources

About