Instability of coral limestone cliffs due to extreme waves

摘要

Many boulders are located around the coastal cliffs with height of below 5 m made of coral limestone at Kuro-shima, Okinawa, Japan. The origin of the boulders appears to be coral limestone cliffs which show developed notches. We undertook stability analysis, involving the wave pressure due to tsunamis, of wave-induced collapse of the cliffs. We find that extreme waves are capable of inducing cliff collapse, as observed in circumstances where gravity is insufficient.