The Province of Manus is a maritime province and comprises of more than 215 islands of which four are large volcanic islands with coral limestone on the surface whilst the rest of islands nearly 211 are made from coral polyps or weak limestone deposited with poor loose soils.
Los Negros Island is large volcanic island with coral limestone on the surface and was fattened during the World War II in 1945. Much of the landscape, soils and environment have been changed as a result of World War II relics and disasters.