The geography of Antarctica is dominated by its south polar location and, thus, by ice. The Antarctic continent, located in the Earth's southern hemisphere, is centered asymmetrically around the South Pole and largely south of the Antarctic Circle. It is washed by the Southern (or Antarctic) Ocean or, depending on definition, the southern Pacific, Atlantic, and Indian Oceans. It has an area of more than 14 million km2. Antarctica is the largest ice desert in the world.
Some 98% of Antarctica is covered by the Antarctic ice sheet, the world's largest ice sheet and also its largest reservoir of fresh water. Averaging at least 1.6 km thick, the ice is so massive that it has depressed the continental bedrock in some areas more than 2.5 km below sea level; subglacial lakes of liquid water also occur (e.g., Lake Vostok). Ice shelves and rises populate the ice sheet on the periphery. The present Antarctic ice sheet accounts for 90 percent of Earth's total ice volume and 70 percent of its fresh water. It houses enough water to raise global sea level by 200 ft.
In September 2018, researchers at the National Geospatial-Intelligence Agency released a high resolution terrain map (detail down to the size of a car, and less in some areas) of Antarctica, named the "Reference Elevation Model of Antarctica" (REMA).
Regions
Physically, Antarctica is divided in two by the Transantarctic Mountains, close to the neck between the Ross Sea and the Weddell Sea. Western Antarctica and Eastern Antarctica correspond roughly to the western and eastern hemispheres relative to the Greenwich meridian.
West Antarctica is covered by the West Antarctic Ice Sheet. There has been some concern about this ice sheet, because there is a small chance that it will collapse. If it does, ocean levels would rise by a few metres in a very short period of time.
Volcanoes
Volcanoes that occur underneath glacial ice sheets are known by the term "Glaciovolcanism", or subglacial volcanoes. An article published in 2017 claims that researchers from Edinburgh University recently discovered 91 new volcanoes below the Antarctic ice sheet, adding to the 47 volcanoes that were already known. As of today, there have been 138 possible volcanoes identified in West Antarctica. There is limited knowledge about West Antarctic Volcanoes due to the presence of the West Antarctic Ice Sheet, which heavily covers the West Antarctic Rift System—a likely hub for volcanic activity. Researchers find it difficult to properly identify volcanic activity due to the comprehensive ice covering.
East Antarctica is significantly larger than West Antarctica, and similarly remains widely unexplored in terms of its volcanic potential. While there are some indications that there is volcanic activity under the East Antarctic Ice Sheet, there is not a significant amount of present information on the subject.
Mount Erebus is one of the most notable sites in the study of Antarctic Volcanism, in that it is the southernmost historically active volcanic site on the planet.
Deception Island is another active Antarctic volcano. It is one of the most protected areas in the Antarctic, given its situation between the South Shetland Islands and the Antarctic Peninsula. As the most active volcano in the Antarctic peninsula, it has been studied closely since its initial discovery in 1820.
There are four volcanoes on the mainland of Antarctica that are
considered to be active on the basis of observed fumarolic activity or
"recent" tephra deposits: Mount Melbourne (2,730 m) (74°21'S., 164°42'E.), a stratovolcano; Mount Berlin (3,500 m) (76°03'S., 135°52'W.), a stratovolcano; Mount Kauffman (2,365 m) (75°37'S., 132°25'W.), a stratovolcano; and Mount Hampton (3,325 m) (76°29'S., 125°48'W.), a volcanic caldera. Mount Rittmann (2,600 m) (73.45°S 165.5° E), a volcanic caldera.
Several volcanoes on offshore islands have records of historic activity. Mount Erebus (3,795 m), a stratovolcano on Ross Island with 10 known eruptions and 1 suspected eruption. On the opposite side of the continent, Deception Island (62°57'S., 60°38'W.), a volcanic caldera with 10 known and 4 suspected eruptions, have been the most active. Buckle Island in the Balleny Islands (66°50'S., 163°12'E.), Penguin Island (62°06'S., 57°54'W.), Paulet Island (63°35'S., 55°47'W.), and Lindenberg Island (64°55'S., 59°40'W.) are also considered to be active. In 2017, the researchers of Edinburgh University discovered 91 underwater volcanoes under West Antarctica.