This computer-generated 3D model of the surface of Venus shows the Sif Mons volcano, which shows signs of continued activity. Using data from NASA’s Magellan mission, Italian researchers detected evidence of an eruption as the spacecraft orbited the planet in the early 1990s. Credit: NASA/JPL-Caltech
Recent analyzes of NASAMagellan radar data revealed two volcanic eruptions on Venus in the early 1990s, adding to earlier discoveries of volcanic activity. These findings suggest that volcanic activity on Venus may be more intense and more frequent than previously thought, indicating a dynamic geological history that contrasts with that of Earth.
For the second time, direct geological evidence of recent volcanic activity on Venus has been observed. Italian scientists analyzed archival data from NASA’s Magellan mission to reveal surface changes indicating the formation of new rocks from lava flows linked to volcanoes that erupted as the spacecraft orbited the planet . Managed by NASA’s Jet Propulsion Laboratory (JPL) in Southern California, Magellan mapped 98% of the planet’s surface between 1990 and 1992, and the images he generated remain the most detailed of Venus to date.
“Using these maps as a guide, our results show that Venus may be much more volcanically active than previously thought,” said Davide Sulcanese of the University of Annunzio in Pescara, Italy, who led the study. study. “By analyzing the lava flows we observed in two places on the planet, we discovered that volcanic activity on Venus could be comparable to that on Earth. »
Maat Mons is displayed in this computer-generated three-dimensional perspective of the surface of Venus. The viewpoint is located 634 kilometers (393 miles) north of Maat Mons, at an altitude of 3 kilometers (2 miles) above the terrain. Lava flows extend hundreds of kilometers across the fractured plains shown in the foreground, all the way to the base of Maat Mons. Synthetic aperture radar data from NASA’s Magellan mission is combined with radar altimetry to develop a three-dimensional map of the surface. The vertical scale in this perspective has been exaggerated 10 times. Credit: NASA/JPL
This latest discovery builds on the historic discovery in 2023 of images from Magellan’s synthetic aperture radar that revealed changes in a vent associated with the Maat Mons volcano near Venus’ equator. Radar images have proven to be the first direct evidence of a recent volcanic eruption on the planet. By comparing radar images of Magellan over time, the authors of the 2023 study spotted changes caused by the flow of molten rock from beneath Venus filling the vent crater and spilling onto the slopes of the vent.
Scientists study active volcanoes to understand how a planet’s interior can shape its crust, drive its evolution and affect its habitability. The discovery of recent volcanism on Venus provides valuable insight into the planet’s history and why it followed a different evolutionary path than Earth.
Radar backscatter
For the new study, published in the journal Natural astronomy, the researchers also focused on archival data from Magellan’s synthetic aperture radar. Radio waves sent by the radar passed through Venus’ thick cloud cover, then bounced off the planet’s surface and back toward the spacecraft. Called backscatter, these reflected radar signals carried information about the rock surface materials they encountered.
The two sites studied were the Sif Mons volcano in the Eistla region and the western part of Niobe Planitia, which is home to many volcanic features. By analyzing backscatter data received from both locations in 1990 and again in 1992, the researchers found that the strength of the radar signal increased along some paths during later orbits. These changes suggest the formation of new rocks, most likely solidified lava from volcanic activity that occurred during this two-year period. But they also considered other possibilities, such as the presence of micro-dunes (formed from wind-blown sand) and atmospheric effects that could interfere with the radar signal.
This full-resolution Magellan mosaic, centered at 12.3 degrees north latitude and 8.3 degrees east longitude, shows an area 160 kilometers (96 miles) by 250 kilometers (150 miles) in the Eistla region of Venus. The prominent circular features are volcanic domes 65 kilometers (39 miles) in diameter with broad, flat peaks less than a kilometer (0.6 mile) high. Sometimes called “pancake” domes, they represent a unique category of volcanic extrusions on Venus formed from viscous (sticky) lava. The cracks and pits commonly found in these formations result from the cooling and retreat of lava. A less viscous flow was emitted from the northeast dome toward the other large dome located in the southwest corner of the image. Credit: NASA/JPL
To help confirm the new rock, researchers analyzed elevation (surface height) data from Magellan to determine the slope of the topography and locate obstacles around which lava would flow.
“We interpret these signals as flows along slopes or volcanic plains that can deviate around obstacles such as shield volcanoes like a fluid,” said study co-author Marco Mastrogiuseppe of Sapienza University. from Rome. “After ruling out other possibilities, we confirmed that our best interpretation is that these are new lava flows. »
Using flows on Earth for comparison, the researchers estimate that the new rocks emplaced in both locations are on average between 3 and 20 meters deep. They also estimate that the Sif Mons eruption produced about 30 square kilometers of rock, enough to fill at least 36,000 Olympic-sized swimming pools. The Niobe Planitia eruption produced approximately 45 square kilometers of rock, which would fill 54,000 Olympic-sized swimming pools. For comparison, the 2022 eruption of Mauna Loa in Hawaii, Earth’s largest active volcano, produced a lava flow containing enough material to fill 100,000 Olympic-sized swimming pools.
“This exciting work provides another example of volcanic change on Venus due to new lava flows that increase the vent change that Dr. Robert Herrick and I reported last year,” said Principal Investigator Scott Hensley. at JPL and co-author of the 2023 study. “This result, in tandem with the earlier discovery of current geological activity, increases the planetary science community’s enthusiasm for future missions to Venus. »
Before beginning its journey to Venus, NASA’s Magellan spacecraft was jettisoned while in Earth orbit by the Space Shuttle Atlantis’ STS-30 mission. Captured in this photo from May 4, 1989, Magellan was the first planetary spacecraft to launch from the shuttle. Credit: NASA
Understanding Volcanoes
Hensley is the project scientist for NASA’s upcoming VERITAS mission, and Mastrogiuseppe is a member of its science team. Short for Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy, VERITAS is expected to launch early next decade, using cutting-edge synthetic aperture radar to create 3D global maps and a near-infrared spectrometer to understand what the surface of Venus is made of while also tracking volcanic activity. Additionally, the spacecraft will measure the planet’s gravitational field to determine its internal structure.
“These new findings of recent volcanic activity on Venus by our international colleagues provide compelling evidence for the type of regions we should target with VERITAS when it arrives on Venus,” said Suzanne Smrekar, senior scientist at JPL and principal investigator. of VERITAS. “Our spacecraft will have a suite of approaches for identifying surface changes that are far more comprehensive and with higher resolution than Magellan’s images. Evidence of activity, even in the lower resolution Magellan data, reinforces the potential to revolutionize our understanding of this enigmatic world.
NASA’s VERITAS mission was selected in 2021 as part of NASA’s Discovery program. Mission partners include Lockheed Martin Space, the Italian Space Agency, the German Aerospace Center and the National Center for Space Studies in France. The Discovery program is managed by the Planetary Mission Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, on behalf of the Planetary Science Division of NASA’s Science Mission Directorate in Washington.
