Subglacial volcanoes are exactly what they sound like—volcanoes buried under ice sheets. Antarctica has at least 138 of them. Probably more that we havent found yet because drilling through 2-3 kilometers of ice to map volcanic features is expensive and difficult.
When volcanoes erupt under ice, the results are dramatically different from normal eruptions. Ice melts instantly, creating massive floods called jökulhlaups. Steam explosions fragment magma into fine ash. The combination can be catastrophic.
How Ice And Fire Create Geological Chaos That Makes Regular Eruptions Look Tame
Iceland has extensive experience with subglacial eruptions. Grímsvötn volcano sits beneath Vatnajökull glacier. It erupts every 5-10 years. The 2011 eruption melted so much ice that floodwaters exceeded the flow of the Amazon River.
The meltwater accumulates under the glacier, building pressure. Eventually it breaks through as a massive flood. The 1996 Gjálp eruption released enough water to wash away bridges and flood plains. Peak discharge: 50,000 cubic meters per second.
Eyjafjallajökull’s 2010 eruption—the one that shut down European airspace—was partly subglacial. Magma melted ice, water interacted with magma, explosions fragmented lava into fine ash that reached the stratosphere. Without the ice, the eruption would have been much less disruptive.
Antarctica’s Hidden Volcanic Activity Nobody Monitors Closely
Mount Erebus is Antarctica’s most famous volcano. It has a persistent lava lake and erupts regularly. But its just one of 138+ volcanoes on the continent. Most sit beneath the West Antarctic Ice Sheet.
We know they exist from seismic data and radar imaging. But we dont know if they’re active. Detecting eruptions under 2 kilometers of ice is nearly impossible unless they melt enough ice to create surface depressions or drain subglacial lakes.
Marie Byrd Land in West Antarctica contains the largest concentration—at least 18 major volcanoes. One study suggested recent eruptions occurred within the last 10,000 years based on radar signatures showing volcanic ash layers in ice cores.
Subglacial eruptions might contribute to ice sheet instability. Heat melts the base of ice sheets, creating meltwater that lubricates ice flow. Whether volcanic activity meaningfully affects ice sheet collapse remains debated, but its a concern.
Why We Should Care About Volcanoes In Places Nobody Lives
Climate records preserved in ice cores can be disrupted by volcanic eruptions. Ash layers help date ice cores, but they also complicate climate signal interpretation. Understanding subglacial volcanism improves ice core analysis.
If West Antarctic Ice Sheet collapses—raising sea level by 3-5 meters—subglacial volcanic activity might be one contributing factor. Probably not the main cause, but ignoring potential influences seems unwise.
Geothermal heat from subglacial volcanoes affects ice sheet dynamics. The base of the ice melts, creating subglacial lakes. Lake Vostok in Antarctica sits above a possible volcanic system. The lake’s existence depends partly on geothermal heating.
We study subglacial volcanoes because they’re there and they affect ice sheets. Because jökulhlaups from Icelandic eruptions threaten infrastructure. Because understanding volcanic processes under ice helps us predict hazards in glaciated regions. Its niche research but somebody has to do it.
