Great Chagos Bank

Great Chagos Bank

The Great Chagos Bank is the largest reef structure with emergent parts to be found in the Indian Ocean and at 13,000 km² is one of the largest on earth, extending for nearly 100 km north to south and for 150 km east to west. The formation consists of an unusual, mostly submerged, atoll-like complex of reefs, banks and islets. Outside the main reef rim are a number of satellite reefs and banks. The bank is the dominant feature of the Chagos Archipelago, and is located 54 km north from Diego Garcia (see panoramic image).

For its size there are relatively few islands on the Great Chagos Bank. On the northern side of the bank is the small Nelson Island (81 ha), measuring 2 km by 1 km. On the west are the three reef-fringed islets of the Three Brothers (Trois Fréres) and Resurgent Islands, comprising: Île du Sud, Île du Mileu, Île du Nord — also known as North (6 ha), Middle (8 ha), and South (23 ha) Brother — and an unnamed islet. A farther 15 km southwest are the two islands that comprise the Eagle Islands (usually referred to as Eagle Island) — consisting of Île Aigle (2.45 km²) and the smaller Île aux Vaches (Cow Island) located 3 km southwest of Île Aigle. Also on the southwest rim, 14 km southwest of Île Aigle, sits the small Danger Island (66 ha). The eastern and southern sides of the bank are completely submerged with no islands. The small islets of the west and north give the Great Chagos Bank a total land area of a mere 6 km².

image: MODIS rapid response project at nasa/goddard space flight center