It is an island archipelago consisting of approximately 82 relatively small, geologically newer islands of volcanic origin (65 of them inhabited), with about 800 miles north to south distance between the outermost islands. Most of the islands are steep, with unstable soils, and little permanent freshwater. The shoreline is usually rocky with fringing reefs and no continental shelf, dropping rapidly into the ocean depths.
Some geographic features of Vanuatu include a group of islands with 2,528 km of coastline, has tropical climate, narrow coastal plains, tropical cyclones between January and April, and active volcanoes. Check out http://geography.about.com/library/cia/blcvanuatu.htm for more details.