scholarly journals Conceptual model of fracture‐limited sea cliff erosion: erosion of the seaward tilted flyschs of Socoa, Basque Country, France

2021 ◽  
Author(s):  
Mélody Prémaillon ◽  
Thomas J. B. Dewez ◽  
Vincent Regard ◽  
Nicholas J. Rosser ◽  
Sébastien Carretier ◽  
...  
Keyword(s):  
Conceptual Model ◽  
Basque Country ◽  
Cliff Erosion ◽  
Sea Cliff

Sea-Cliff Erosion at Pacifica, California, Caused by 1997-98 El Niño Storms

2000 ◽  
Author(s):  
Charles B. Snell ◽  
Kenneth R. Lajoie ◽  
Edmund W. Medley
Keyword(s):  
El Niño ◽  
El Nino ◽  
Cliff Erosion ◽  
Sea Cliff

scholarly journals The influence of wave power on bedrock sea-cliff erosion in the Hawaiian Islands

Geology ◽  
2020 ◽  
Vol 48 (5) ◽  
pp. 499-503 ◽  
Author(s):  
Kimberly L. Huppert ◽  
J. Taylor Perron ◽  
Andrew D. Ashton
Keyword(s):  
Sea Level ◽  
Coastal Erosion ◽  
Wave Power ◽  
Relative Sea Level ◽  
Cliff Erosion ◽  
Field Evidence ◽  
Coastal Profile ◽  
Sea Cliff ◽  
Best Fit ◽  
Cliff Retreat

Abstract Waves erode sea cliffs by various mechanisms, but the influence of wave power on bedrock coastal erosion has not been well quantified, making it difficult to predict how rocky coasts evolve in different environments. Volcanic ocean islands offer a unique opportunity to examine the influence of waves on bedrock coastal erosion because many islands have relatively homogeneous bedrock, well-constrained initial topography, and considerable differences in wave power between shorelines that face different directions and wave regimes. We used lava-flow ages and the morphology of coastal profiles on Maui, Kaho‘olawe, and the Big Island of Hawai‘i (USA) to estimate sea-cliff retreat rates at 11 sites that experience nearly eightfold differences in incident wave power. Using a range of possible sea-level histories that incorporate different trends of subsidence due to volcanic loading, we modeled the evolution of each coastal profile since its formation (12 ka to 1.4 Ma) to find the regionally consistent relative sea-level history and the site-specific sea-cliff retreat rates that best reproduce observed coastal profiles. We found a best-fit relative sea-level history prescribed by an effective elastic lithosphere thickness of 30 km, consistent with estimates from observations of total deflection beneath the Hawaiian Ridge. This suggests that coastal profiles may retain a decipherable record of sea-level change. Comparing the best-fit sea-cliff retreat rates to mean annual wave power at each site, which we calculated from 30 yr hindcast wave data, we found a positive relationship between wave power and sea-cliff erosion, consistent with theoretical predictions and measurements on unlithified coastal bluffs. These comparisons provide field evidence that bedrock coastal erosion scales with wave power, offering a basis for modeling rocky coast evolution in different wave climates.

scholarly journals Sea-cliff Erosion with Rising Sea-Level along Shores Exposing Glacial Material in Atlantic Canada: The Effect of Bedrock Slope and an Example from Isle Madame, Nova Scotia

2013 ◽  
Vol 40 (1) ◽  
Author(s):  
Eric R. Force
Keyword(s):  
Nova Scotia ◽  
Sea Level ◽  
Limiting Factor ◽  
Atlantic Canada ◽  
Cliff Erosion ◽  
Coastal Retreat ◽  
Bedrock Surface ◽  
Sea Cliff ◽  
Le Canada ◽  
Rising Sea Level

Rapid retreat rates of sea cliffs exposing glacial material are a widespread problem, especially in Atlantic Canada, and one that will continue. Prediction of retreat rates at specific sites involves many variables, but a factor that has commonly been overlooked in such prediction is the slope of the bedrock surface under the glacial material. A glaciated bedrock platform is generally necessary to establish a stable situation of temporary equilibrium, and as sea-level rises, the bedrock slope determines the location of the new equilibrium position. An example from Nova Scotia shows that bedrock slope is so low on some coasts that the only long-range limiting factor is kinetic, i.e. how fast hydrodynamic energy can remove glacial material. Prediction of coastal retreat scenarios requires better information on the bedrock surface than is commonly available.SOMMAIRELes taux de retrait rapide des falaises qui exposent des matériaux glaciaires est un problème très répandu et qui va perdurer, surtout dans le Canada atlantique. La prévision des taux de retrait sur des sites spécifiques comporte de nombreuses variables et, la pente du substratum rocheux sur lequel reposent ces matériaux glaciaires et une variable qui a souvent été négligée. L’existence d’un substratum rocheux glacié est généralement une condition nécessaire pour l’établissement d’une situation d'équilibre stable temporaire, et lorsque le niveau de la mer monte, la pente du substratum rocheux a une influence déterminante sur le lieu de la nouvelle position d'équilibre. Un exemple en Nouvelle-Écosse montre que la pente du substratum rocheux est si faible sur certaines côtes que le seul facteur déterminant à long terme est la cinétique, c'est-à-dire la vitesse d’abrasion du matériau glaciaire correspondant à l’énergie hydrodynamique. La prévision des scénarios de retrait de la ligne côtière requière une meilleure connaissance du substratum rocheux. 

Role of discontinuities in spatial pattern of sea cliff erosion: case of a seaward dipping flysch cliff (Socoa, Basque Country, France)

2020 ◽  
Author(s):  
Vincent Regard ◽  
Melody Prémaillon ◽  
Thomas J. B. Dewez ◽  
Nick J. Rosser ◽  
Sébastien Carretier
Keyword(s):  
Basque Country ◽  
Aerial Photographs ◽  
Erosion Rates ◽  
Rock Structure ◽  
Bed Thickness ◽  
Major Factors ◽  
Sea Cliff ◽  
Control Erosion ◽  
Term Data

<p>Sea cliff shapes and erosion rates are controlled by several factors. Among them, rock resistance, whose strength results from lithology and rock structure, are pointed as major factors. Erosion is expected to focus on discontinuities where the rock mass is weakest (faults, fractures, joints and strata bounds), but understanding the control of discontinuities on the spatial and temporal pattern of erosion remains challenging. To analyze and quantify how rock structures control erosion, we monitored the evolution of a 400-m-long stretch of well-structured sedimentary cliffs: the Socoa cliff (Basque Country, France). The rock, known as the Socoa flysch formation, is a 45°-seaward-tilted, shore-parallel-striking, decimeter-thick repeating sequence of sandstone, mudstone, marl and limestone beds. Cliff-face erosion was observed and quantified using 6 ground-based Structure-from-Motion (SfM) surveys, spanning 5.7 years between 2011 and 2017.  To compare with longer term data, a multi-decadal (54 years) cliff-top retreat rate was also assessed using SfM-orthorectified archive aerial photographs spanning the period 1954-2008. During the ground-based survey, the 13 250 m² cliff face released 4500 blocks larger than 1.45*10<sup>-3</sup> m<sup>3 </sup>for a total rock volume eroded of 170 m<sup>3</sup>. This rock lost volume equates to an average cliff retreat rate of 3.4 mm/yr. It is slightly slower than the 54 years-average cliff top retreat rate of 10.8 ± 1.8 mm/yr. In elevation, the maximum erosive activity is positioned about 2 m above high spring tides. The geographic position of rock scars is controlled by tectonic discontinuities. Alongshore, hot-spots of erosion are focused where major faults cross-cut the cliff face. Around these geographic hotspots, the depth of detached blocks is controlled by bed thickness, removing one or several beds at once. The surficial extent of detached blocks on the cliff-face is controlled by orthogonal secondary tectonic joint sets. These joints do not stop on lithological bed limits but rather on mechanical limits encompassing several lithological beds at once. As a process, we explain block detachment and cliff collapse by a cycle of erosion nucleation on discontinuities, radial erosion propagation around the nuclei and finally, cliff collapse crisis affecting the cliff top. We demonstrate that block production is concentrated around faults (nucleation) that focus erosion and allows for the radial development of sea caves close to cliff foot. Then, block production occurs mainly around those caves by radial detachment processes at free edges or fractures (propagation). It may lead, exceptionally, to high-magnitude events, during which slab collapse can affect the cliff from base to top (crisis).</p>

scholarly journals Fluid-Elastoplastic Hybrid Model for Computational Mechanics of Wave-Induced Sea Cliff Erosion

2010 ◽  
Vol 66 (1) ◽  
pp. 916-920 ◽  
Author(s):  
Hiroyuki IKARI ◽  
Hitoshi GOTOH ◽  
Tomoyuki ARAI
Keyword(s):  
Hybrid Model ◽  
Computational Mechanics ◽  
Cliff Erosion ◽  
Wave Induced ◽  
Sea Cliff

Characteristics of sea-cliff erosion induced by a strong winter storm in the eastern Mediterranean

2013 ◽  
Vol 80 (1) ◽  
pp. 20-32 ◽  
Author(s):  
Oded Katz ◽  
Amit Mushkin
Keyword(s):  
Transient Stability ◽  
Eastern Mediterranean ◽  
High Energy ◽  
Storm Events ◽  
Winter Storm ◽  
Cliff Erosion ◽  
Decadal Scale ◽  
Lidar Measurements ◽  
Gravity Driven ◽  
Sea Cliff

Changes in sea-cliff morphologies along the 30-km-long Sharon Escarpment segment of Israel's weakly cemented Mediterranean eolianite cliff line were analyzed to gain quantitative insights into erosion characteristics associated with a high-energy winter storm (10–20 year return interval). Ground-based repeat LiDAR measurements at five sites along the cliff line captured perturbations of cliff stability by basal wave scouring during the storm, subsequent post-storm gravity-driven slope failures in the cliff face above, and return of the system to transient stability within several months. Post-storm erosion, which amounted to 70% of the total volume of cliff erosion documented, resulted in dramatic local effects of up to 8 m of cliff-top retreat. And yet, at the larger scale of the 30-km cliff line examined, erosion during the storm and the year that followed affected less than 4% of the cliff length and does not appear to be above the average cliff-length annual erosion implied by previously published decadal-scale retreat rates along this sea cliff. Our results do not support a direct association between strong storm events and elevated erosion and retreat at the cliff-line scale.

Sea Cliff Erosion in the Eastern Part of the North Aegean Coastline, Northern Greece

2006 ◽  
Vol 41 (9) ◽  
pp. 1989-2011 ◽  
Author(s):  
GEORGE S. XEIDAKIS ◽  
P. K. DELIMANI ◽  
S. G. SKIAS
Keyword(s):  
Northern Greece ◽  
Cliff Erosion ◽  
The North ◽  
North Aegean ◽  
Sea Cliff

scholarly journals Assessing the applicability of UAV for Sea Cliff Erosion-rate Monitoring

2017 ◽  
Vol 27 (2) ◽  
pp. 1-13
Author(s):  
Kim Jang-soo
Keyword(s):  
Erosion Rate ◽  
Cliff Erosion ◽  
Sea Cliff
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