A study of the effect of shore platform morphology on coastal erosion of rocky cliffs in the Wucaiwan Bay,E'man,Hainan Island
The intensification of extreme wave marine hazard induced by global ocean change is very likely to accelerate the geo-hazard risk of cliff erosion in Hainan Island.Shore platforms are expected to effectively attenuate wave energy approaching the shore and consequently reduce the erosive impact of extreme waves on cliff.Shore platforms are commonly observed in volcanic rocky coasts on NW Hainan Island,providing an ideal natural laboratory to evaluate the effect of shore platform morphology on cliff erosion.This study employs the Wucaiwan Bay rocky coastline in the E'man Town,Danzhou City,Hainan Island as the study area.Time-lapsed marine remote sensing images revealed the cliff erosion rate is about 0.26 m·a-1 in the last decade in the area.Physical oceanography analysis suggested a maximum significant wave height of 7.8 m could be expected visiting the area in a 100-years return level.The geomorphological characteristics of the sloping shore platform and the rock strength of cliffs were further surveyed via coastal geomorphological approaches.Numerical computation outputs suggest the shore platforms is capable of reducing the wave erosional forces on cliff by over 80%under future extreme wave conditions.This study further discusses the natural coastal protection from sediment beaches,vegetations and in situ deposition of eroded boulders at rock cliff foot.
shore platformcliff erosionbasalt coastnumerical computationHainan Island
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NSTL
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