Magellan imaged portions of Venus up to three times spanning 24 months from 1990 to 1992.
Venus is covered with craters, volcanoes, mountains and lava plains. "Although it is possible the vent collapse was not associated with active volcanism, on Earth this large a collapse is usually associated with some sort of magmatic movement, and hence we think it likely to be the case here," said study co-author Scott Hensley, a senior research scientist specializing in radar remote sensing at NASA's Jet Propulsion Laboratory in California. The vent is located on the north side of a larger volcanic structure just off the main summit of Maat Mons. "Our interpretation is that there is a new influx of magma into a chamber underneath the vent, and that results in formation of a broader, irregular caldera (a large depression created when a volcano erupts and collapses) that still has an active lava lake in it when the second image is taken," Herrick said. "What we definitively can demonstrate is that a volcanic vent got larger and looks to have gone from conical and hundreds of meters deep in its interior to a flat, nearly filled interior," said Robert Herrick, a University of Alaska Fairbanks Geophysical Institute research professor and lead author of the study published in the journal Science. An October 1991 image showed the vent with an irregular shape covering about 1.5 square miles (3.9 square kilometres). The vent is situated on Maat Mons, which at about 5 miles (9 km) tall is the planet's highest volcano and second-highest mountain.Ī February 1991 image showed the vent as a circular formation covering about one square mile (2.6 square kilometres).
Researchers said on Wednesday radar images taken by NASA's Magellan spacecraft showed that a volcanic vent about a mile (1.6 km) wide on the Venusian surface expanded and changed shape over an eight-month span in 1991. A fresh analysis of radar images obtained more than three decades ago has yielded new evidence indicating Venus, Earth's planetary next-door neighbour, is currently volcanically active - a dynamic world with eruptions and lava flows.
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