Geography of Antarctica

Antarctica is a massive continent located in the Earth's Southern Hemisphere. It is centered asymmetrically around the South Pole. The continent is largely situated south of the Antarctic Circle. It is surrounded by the Southern Ocean. Depending on how you define it, it also touches the Pacific, Atlantic, and Indian Oceans. Antarctica is the largest ice desert on our planet.

The geography of the continent is defined by the Antarctic ice sheet. This ice sheet covers about 98% of the land area. It is the largest ice sheet in the world. This massive frozen layer holds 90% of Earth's total ice volume. It also contains 70% of the world's fresh water. The ice is so heavy that it depresses the continental bedrock. In some areas, the land sits below sea level. There are even subglacial lakes of liquid water, such as Lake Vostok.

Researchers can now see the land through the ice using technology. In September 2018, the National Geospatial-Intelligence Agency released a high-resolution terrain map. This is called the Reference Elevation Model of Antarctica, or REMA. The map shows details as small as a car.

It is important to note that this map shows the land without ice. It does not account for rising sea levels if the ice melted. It also does not show how the land might rise after the ice weight is gone.

The continent is physically divided into two main regions. The Transantarctic Mountains create this division. These mountains sit near the neck between the Ross Sea and the Weddell Sea. The two regions are West Antarctica and East Antarctica. West Antarctica is the smaller part of the continent. It is covered by the West Antarctic Ice Sheet. Some scientists worry this ice sheet might collapse due to rising temperatures. Such a collapse could raise global ocean levels by a few metres.

East Antarctica is significantly larger than West Antarctica. This larger side contains both the South Magnetic Pole and the geographic South Pole. Volcanic activity also plays a major role in the landscape. This is known as glaciovolcanism, which is volcanic activity occurring beneath ice sheets. In 2017, researchers from the University of Edinburgh discovered 91 new volcanoes. These were found beneath the Antarctic ice sheet. This discovery added to the 47 volcanoes that were already known.

West Antarctica is a major hub for this volcanic activity. The West Antarctic Rift System is a likely center for volcanoes. As of 2017, researchers identified 138 possible volcanoes in this region. It is difficult to study them because the ice is so thick. Scientists look for ash layers or seismic activity to find them. Seismic activity involves movement in the Earth's crust. This can hint at the movement of magma. In Marie Byrd Land, volcanoes are often made of basaltic lava. These subglacial volcanoes can be narrow or wide depending on their type.

Some volcanoes in Antarctica are well-known and active. Mount Erebus is the southernmost historically active volcanic site on Earth. It is a stratovolcano located on Ross Island. Deception Island is another active volcanic caldera. It is located between the South Shetland Islands and the Antarctic Peninsula. There are also four active volcanoes on the mainland. These include Mount Melbourne, Mount Berlin, Mount Kauffman, and Mount Hampton.

These sites help scientists understand how heat affects the ice.

Volcanic activity can create significant hazards in the region. Eruptions can cause melting of the ice sheets. This could create a positive feedback loop of rising temperatures and more melting. There is also the risk of volcanic ash. If ash enters the Stratospheric jet streams, it could disperse globally. This would create hazards for aviation and human health. Finally, huge canyons called troughs exist under the ice. The Foundation Trough is the largest of these. These canyons are hidden under hundreds of meters of snow and ice.