Analysis on the Process and Factors which Influence Erosion Recession in the Soft Sea Cliff on Haitan Island over the past 50 Years

摘要

The soft sea cliff is an important type of erosion coast due to its fasterosion recession speed. It has become a hot point in research into coasterosion. In this paper, short term change in a section of the sea cliffalong the Liushui coast on Haitan Island is researched. This is donethrough field investigations and a topographic survey. Meanwhile, thelong term evolution of the coastline over 50 years is analyzed. This wasdone by referencing remote sensor image data from seven differentperiods. Major influence factors related to erosion recession of the seacliff are discussed further. The findings show that from the view ofshort term change, the recession of a sea cliff occurs according to fourcoast types (higher cliff coast, lower cliff coast covered by sand dune,artificial coast and sand dune coast). This recession occurs at differentdegrees, among which the erosion recession of the low sea cliff isrelatively small. Here, the down-cutting of the beach face on a artificialcoast is relatively obvious. Over 50 years, the general change trend forthe coastlines was a recession towards land. Here, the coastlineincreases slowly and loss of land area is severe. The erosion of a seacliff is an accumulation that progresses from short term change to longterm evolution. In this regard, the lithology of the sea cliff, localclimatic conditions, waves, storm tides, tidal currents and otherdynamic ocean conditions are important factors. With continuous riseof sea levels, the speed of erosion recession of sea cliffs will alsoincrease.