Wave transformation on a sub-horizontal shore platform, Tatapouri, North Island, New Zealand

Ogawa, Hiroki; Dickson, Mark E.; Kench, Paul S.

doi:10.1016/j.csr.2011.05.006

Cited by 63 publications

(98 citation statements)

References 35 publications

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“…These observations match those of recent studies that have used transects of pressure sensors to measure the cross-shore distribution of wave energy, and the corresponding wave spectra, on rock foreshores. Both are dependent on the foreshore morphology and cliff toe elevation relative to the tidal range (Ogawa et al, 2011(Ogawa et al, , 2016Poate et al, 2016;Stephenson et al, 2017). At sites with large macrotidal ranges (i.e.…”

Section: The Influence Of Foreshore Morphology On Ht Ground Motion Enmentioning

confidence: 99%

“…Stephenson and Kirk, 2000;Trenhaile and Kanyaya, 2007), and have measured the distribution of wave energy cross-shore and the influence of foreshore characteristics (Ogawa et al, 2011(Ogawa et al, , 2016Poate et al, 2016;Stephenson et al, 2017). Such studies have not considered alongshore variability in these foreshore characteristics, the resulting wave energy dissipation and transfer to the cliff.…”

Section: Introductionmentioning

confidence: 99%

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Alongshore variability in wave energy transfer to coastal cliffs

2018

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The alongshore distribution of wave energy is believed to be an important control on the spatial variability of coastal erosion. There is, however, a lack of field data quantifying the alongshore variability in wave energy on rock coasts, whereby the relative control of coastline geometry versus foreshore characteristics on wave energy delivery remains unclear. A number of studies have identified high-frequency cliff-top ground shaking to be generated by wave impacts at the cliff toe during high tides (HT). To capture the variability of wave-cliff impact energy along-coast, we installed an array of cliff-top seismometers along a 1 km stretch of coastline in North Yorkshire, UK. Our aim is to constrain how wave energy transfer to the cliff toe varies, and to examine the relative energy transfer around typical coastline features, including a bay and headlands. Whilst the greatest HT ground motion energy is recorded at a headland and the lowest at the centre of the bay (5% of that observed at the headland), we identify no systematic alongshore variation in the HT ground motion energy that can be related to coastline morphology. We also note considerable variation between features of similar form: the total HT ground motion energy at one headland is only 49% of the next headland 1 km alongshore. Between neighbouring sites within the bay, separated by only 100 m, we observe up to an order of magnitude difference in ground motion energy transfer. Our results demonstrate the importance of the foreshore in driving the variations in energy delivery that we observe. Local alterations in water depth and foreshore topography control the alongshore distribution of wave energy available to generate cliff HT ground motions. Importantly, this apparently local effect overrides the influence of macroscale coastal planform morphology, which has previously been assumed to be the dominant control. The results show that foreshore characteristics that hold influence over wave energy transfer vary significantly over short (~100 m) distances, and so we expect erosion controlled by wave impacts to vary over similar scales.

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Section: The Influence Of Foreshore Morphology On Ht Ground Motion Enmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Alongshore variability in wave energy transfer to coastal cliffs

2018

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“…Stephenson & Kirk's (2000a) work was the first, concluding that waves exert little effect on platform development at Kaikoura, New Zealand. Hydrodynamic research on type B platforms has been recently performed also in New Zealand by Beetham & Kench (2011) and Ogawa et al (2011Ogawa et al ( , 2012: they have elucidated not only the process of wave attenuation but also the presence of infragravity waves that influence wave behaviour on platforms. However, infragravity waves themselves have no direct effect of erosion on the landward cliff, but they act as an energy carrier of the waves which have the potential to cause erosion and control the elevation of the assailing force of waves.…”

Section: A Physical Model For Type B Platform Development In Japanmentioning

confidence: 99%

“…Prior to application of equation (17) to type B platform development, determination of the two coefficients a and b will be made using data obtained from a subhorizontal type B platform at Tatapouri, North Island, New Zealand by Ogawa et al (2011). It should be noted that the data are limited in quantity and have been collected under calm sea conditions.…”

Section: A Physical Model For Type B Platform Development In Japanmentioning

confidence: 99%

Chapter 12 The rock coast of Japan

Sunamura¹,

Tsujimoto

Aoki

2014

Memoirs

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The Japanese islands, situated in a tectonically unstable region with a highly variable geology, are exposed to high wave energy and microtidal environments in most locations. Rocky coasts are common, most having a steep cliff with coastal recession being primarily driven by wave erosion. A fundamental relationship between recession and wave force is obtained through reanalysis of previous laboratory data. On the basis of this relation a model is constructed for the development of type B platforms, that is, horizontal or subhorizontal platforms that have a steep scarp at the seaward edge. The process of wave attenuation on this type of platform and weathering-induced strength reduction of rocks are incorporated into the model. The model is applied to the southwestern coast of the Kii Peninsula and a platform at Ebisu-jima of the Izu Peninsula. Long-term development rates of platforms in the former area are examined: the model indicates that the rate of erosion when platforms were initiated at 6000 years BP is two orders of magnitude greater than present. At the Ebisu-jima platform, wave-induced erosion processes are explored on a daily basis: the model provides a description of temporal variations in platform growth, although the result is not fully satisfactory.Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.

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“…As a result, the transformation of wave energy from gravity to infragravity frequencies is now being quantified through field deployments of pressure sensors (e.g. Ogawa et al 2011;Marshall & Stephenson 2011;Beetham & Kench 2011) and individual pebbles traced in the littoral zone using radio-frequency identification tags (e.g. Benelli et al 2012).…”

mentioning

confidence: 99%