Most volcanic islands rise from abyssal depths in the ocean Oehler et al and have rugged or mountainous interiors with a wide range of summit elevations. It is often observed that steep slopes and dense tropical forest cover limit the use of interior lands for settlement on many islands. As a result, community development, roads, and other infrastructure are concentrated largely along the coastal margin increasing exposure to coastal hazards.

High volcanic islands are often surrounded by protective fringing or barrier reefs. This may enclose lagoons of varying sizes Darwin, Nunn 1994. Larger islands may also have major rivers, creating flood hazards and delivering large quantities of sediment. This can dominate coastal morphology. Sometimes in the vicinity of their outlet extreme rainfall can trigger high runoff landslides and debris flows Mimura and Nunn,1998. For example, Barren Island, Andaman, India is the only active volcano located in the Indian Territory. The volcano vent is located in the northern part and the southern part is rugged and several endemic plants Macaranga sp. Ficus spare found here. Taveuni is a volcanic island located in Fiji and it is a shield volcano that rises from the floor of the Pacific Ocean.

Many tropical islands are of volcanic origin and often have very High Mountain ridges think of Hawai. Since the winds in that region blow predominantly from one direction. On the windward side of an island, the wind-exposed side receives much more precipitation than the other side leeward side. Why is that? Air increases in water content with increasing altitude.

higher altitude increases in water content, O The lee-ward side of an island is in the wind shadow of the mountains still air is always very dry. O Wind is always bringing rainfall. 0 It has not to do with the air forced up the mountain. Rather the rain on the dry side of the mountain is blown into the ocean and does not land on the island. The moist ocean air is forced up the mountains to cool and water condenses.