Volcanic Activity Recorded on Venus: NASA’s Magellan Reveals

VIVA – When scientists took a closer look at archival photographs of Venus' surface, they found something new – evidence of volcanic activity there.

The NASA Magellan spacecraft captured the image in the early 1990s as it circled our nearest planetary neighbor, which is similar in size and composition to Earth. A new analysis of the orbiter’s perspective of a region near the Venusian equator reveals a volcanic vent that changed shape and increased greatly in size over eight months.

The images of the vent represent the first direct geological evidence of recent volcanic activity on the surface of Venus, according to the researchers. A study detailing the findings was published Wednesday in the journal Science, and it was presented at the 54th Lunar and Planetary Science Conference in The Woodlands, Texas, United States.

The Magellan mission became the first one to image the entire surface of Venus before the spacecraft intentionally plunged into the planet’s hot, toxic atmosphere in 1994 to collect a final set of data. But a fleet of new missions will head for Venus within a decade, including VERITAS, the Venus Emissivity, Radio Science, InSAR, Topography, And Spectroscopy mission.

The orbiter will use its instruments to uncover the secrets behind why a planet similar in size to Earth became covered in volcanic plains and topped with an inhospitable atmosphere.

“NASA’s selection of the VERITAS mission inspired me to look for recent volcanic activity in Magellan data,” said lead study author Robert Herrick, a research professor at the University of Alaska Fairbanks and member of the VERITAS science team, in a statement.

“I didn’t expect to be successful, but after about 200 hours of manually comparing the images of different Magellan orbits, I saw two images of the same region taken eight months apart exhibiting telltale geological changes caused by an eruption,” Herrick added.

Herrick also spotted the changes in images of Atla Regio, a vast highland region home to two of Venus’ largest volcanoes, called Ozza Mons and Maat Mons.

Both are similar to Earth’s largest volcanoes, but because they have lower slopes, the two Venusian volcanoes are more spread out, Herrick informed. 

He noticed that a volcanic vent on the north side of a domed volcano that was part of Maat Mons changed between February and October 1991. Magellan’s image of the vent from February showed a circular vent spanning less than 1 square mile (2.2 square kilometers) with steep interior sides and areas of drained lava on the slopes.