A Consideration Concerning Shelves around Islands

The investigation of the shelves around an island has a considerable significance on the study of the continental shelf. The writer tried to compare the width of the shelves around the islands in Japan Sea. 1. The strike of some islands in Japan Sea corresponds to the strike of the shelves. The submarine topograrahy around an island may suggest some relations with the topography on the island. 2. Shelves around the islands are, in general, wider on the western side than on the eastern side. This is due to the difference in marine erosion by the western wind on the exposed and the lee side coast. 3. There is a large variation of width among the shelves around these islands. The period of the formation of an island may be one of the most important factors forming the variation. The writer showed such relationship in the case of Izu islands and Ogasawara islands.