Antarctic Volcano Erupts Beneath Ice

As molten rock flows into a frigid sea, forming new land, and clouds of hot steam rise from melting ice and boiling waters, a previously inactive volcano comes out of retirement. Meanwhile, a heat-sensing satellite alerts scientists for the first time that red-hot lava spews once more from the formerly silent peak beneath the ice of a remote island in the frigid South Atlantic.

Studying the interaction between ice and lava on ice-covered volcanoes helps scientists detect and predict dangerous floods and mudflows that occur when eruptions melt large amounts of frozen water in cold regions such as Antarctica and the more populated Iceland.

Encased in a thick sheet of ice, Montagu Island, the volcanic land mass whose size has increased by an area of about 45 football fields over a month, is part of the South Sandwich Islands, located about 1,200 miles north of Antarctica and east of the southern tip of South America.

In 2001, the once-quiet crater of Montagu Island’s main peak, ice-covered Mount Belinda, began emitting lava and dark clouds of ash, steam, and noxious gases. “Then suddenly, towards the end of September, the crater filled with lava and it has been running ever since,” said John Smellie, a volcanologist who has been studying Mount Belinda since satellites first detected the eruption in 2001. New satellite images taken this November show that lava, flowing sometimes underneath the thick icecap and spilling into the ocean, cools and solidifies, extending the island’s coastline.

What makes Mount Belinda unique is that the world was first alerted to its new activity through a computerized detection system that uses satellite cameras to keep an eye on volcanoes worldwide. Scientists at the Hawaii Institute of Geophysics and Planetology have developed the automated MODVOLC system for monitoring the Earth’s surface temperature by looking at changes in the amount of infrared light, or heat, given off by certain areas of the globe.

“The Earth’s surface is, say, 30 degrees Celsius,” said Robert Wright, one of the researchers who developed the system. “Lava when it is erupted is one thousand degrees Celsius.” This dramatic difference in temperature registers as a thermal anomaly, or “hot spot,” in an infrared image of Earth’s surface. The MODVOLC program sends this information to a website, which scientists monitor to detect new or changing volcanic activity.

“This is the first time the system has actually discovered an eruption of a volcano that has had no previous history of eruption,” said Wright. The MODVOLC system has been operating since February of 2000. In 2001, while Wright was examining images of a volcano located on an island further north, he said, “I noticed another hot spot on one of the islands to the south.” He looked in a database of known active and inactive volcanoes and identified that the new activity was coming from Mount Belinda, for which scientists had no earlier records of eruption.

Volcano researchers often use satellites to monitor the size and direction of lava flows, the movement and composition of ash clouds, as well as the changes in shape and size of Earth’s surface features due to volcanic activity. However, these observations are typically made only after scientists have detected new volcanic activity via ground-based equipment.

Conditions on Montagu Island are so hazardous that researchers have been unable to make ground-based observations of the volcano. Despite advances in technology for overhead observation, the elusive lava flows are often completely hidden by overlying ice sheets or obscured from satellite view by passing clouds. Aerial photography gives scientists a chance to get a higher resolution image of Earth’s surface and avoid the problem of cloud cover.

John Smellie of the British Antarctic Survey, a group that studies the history of Antarctic ice sheets, hopes to fly over Montagu Island next March to get aerial photos of Mount Belinda in action, which will give a more detailed picture of how the lava is interacting with the ice and let them see angular and side views of the changing landscape. Of particular interest to Smellie is the rare formation of a lava delta — a wedge-shaped extension to the island’s coastline. “Only Hawaii has an example happening today,” said Smellie, “so the Montagu delta may yield additional insights.”

by Molly F. Wetterschneider (December 11, 2005)