Abstract
The Idû volcanic islands are surrounded by high sea-cliffs which are very prominent, especially on the basaltic andesite cones, such as Osima, Tosima, Miyakezima, and Hati jozima. The differences in the heights of these cliffs according to their directions are explained largely by the prevailing wind numbers. Besides the wind the “Doyunami” (Large swells common in the summer months) have a considerable influence, so that there is a relation between the height of the cliffs and the forces of its abrasion.
