Atoll Atoll An atoll (, , , , or ), sometimes called a coral atoll, is a ring-shaped coral reef including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. The coral of the atoll often sits atop the rim of an extinct seamount or volcano which has eroded or subsided partially beneath the water. The lagoon forms over the volcanic crater or caldera while the higher rim remains above water(s) or at shallow depths that permit the coral to grow and form the reefs. For the atoll to persist,
Gaafu Alif Atoll Gaafu Alif Atoll Gaafu Alifu (also known as Northern Huvadhu Atoll or Huvadhu Atholhu Uthuruburi) is an administrative division of the Maldives created on February 8, 1962 when Huvadhu Atoll was divided into two districts. Gaafu Alifu corresponds to the northeastern section of this large natural atoll north of the line extending between the channels of Footukandu and Vaarulu Kandu. The capital of this district is Vilingili. NOTE: "Haa Alifu, Haa Dhaalu, Shaviyani, Noonu, Raa, Baa, Kaafu, etc. (including Gaafu Alif) are code letters assigned to the present administrative divisions of the Maldives. They are not the proper names of