A DIMENSIONLESS PARAMETER DESCRIBING SEA CLIFF EROSION

Akira Mano, Shigenori Suzuki

Abstract


Macroscopic analysis based on the energy conservation on sea cliff erosion gives a dimensionless parameter including recession rate of the cliff, wave energy flux at the breaking point, Young's modulus of rocks composing the cliff, and cliff height. This parameter was examined through field data on the Pukushima Coast where a series of soft rock cliffs extends about 50 km. The modulus was obtained by the measurement of the propagation velocity of elastic waves in the rocks and the energy flux was evaluated by the wave ray method. The long-term recession rate had been obtained from the aerial photographs. The recession rate is shown to be proportional to the wave energy flux and inversely proportional to Young's modulus. These quantities prove that the dimensionless parameter has the constant value of 0.082.

Keywords


erosion; cliff; dimensionless parameter

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