学会誌「自然災害科学」

1992年の鳥取県弓ケ浜における海岸侵食の発生機構に関する調査研究

Study on The Mechanism of Coastal Erosion Occured at Yumigahama Beach in 1992

名合 宏之*・前野 詩朗*

Hiroshi NAGO* and Shiro MAENO*

Abstract

In 1992, a large scale coastal erosion occurred at Yumigahama beach in Tottori prefecture with a level difference of about 2 m. In this study, to understand the mechanism of this coastal erosion, we made researches of the characteristics of waves attacked this area and of the changes in seabed profile for the past twenty years in addition to several field observations. Furthermore, the relation between the dynamic behavior of sand bed under wave motion and the coastal erosion was investigated theoretically. The results showed that this area has been subjected to long term beach diminishing process under the imbalance of sediment transport and the actively changing coastal area is closely related to the wave induced liquefied zone. It may be concluded that this large scale erosion was caused by the superposed effect of two factors; one is the long term factor due to the imbalance of sediment transport and the other is the short term one due to the dynamic behavior of sand bed such as liquefaction.

キーワード:

Key words: