Venus is one of the most hostile worlds in the solar system. Surface temperatures reach several hundred degrees Celsius, and the planet has no oceans comparable to those on Earth. For many years, scientists considered Venus geologically inactive. More recent findings, however, suggest that the planet is still geologically “alive” and may even contain active volcanoes.
Among the strongest signs of tectonic activity are Venus’s enormous rift valleys. Similar formations exist on Earth, including the African Rift Valley, but the Venusian versions can extend for as much as 10,000 kilometers.
Are Venus’s Rift Valleys Still Active?
Scientists have not been certain when these vast rifts formed. Many geoscientists have assumed that they developed more than 100 million years ago and are simply ancient features preserved on the planet’s surface.
A new study from ETH challenges that view. Researchers led by Taras Gerya, Professor of Geodynamics at the Department of Earth and Planetary Sciences, used an advanced computer model to show that some of Venus’s rift valleys may be much younger than previously believed. Their work also offers new evidence in the long-running debate over whether Venus remains geologically active.
The study was published in Nature Geoscience. Lead author Xi Yang completed the research during his Master’s studies under Gerya’s supervision.
New 3D Simulations Reveal Young Rifts
Yang and his colleagues created the first high-resolution, 3D computer simulations of Venusian rifts. These models allowed the team to reproduce the structures in greater detail and develop more accurate explanations for how they formed.
Previous simulations were largely two-dimensional and depended on simplified assumptions about the behavior of planetary materials. The new approach gave the researchers a more realistic view of how Venus’s crust stretches, shifts, and relaxes over time.
The results show that broad elevated ridges, called rift flanks, develop along the sides of rift valleys when the rifts are geologically young. These raised features appear while the rifts are still moving or soon after the movement stops.
The simulations also indicate that Venusian rifts may spread faster than scientists once estimated. According to the model, they can widen by about 3 to 10 centimeters each year.
Rift Flanks Fade as the Crust Relaxes
The researchers found that rift flanks begin to flatten relatively quickly once tectonic movement ends. As a rift system ages, its ridges become lower, broader, and less sharply defined.
This process differs from what happens on Earth. Here, erosion gradually wears down mountains and other landforms. On Venus, the rift flanks sink because the crust slowly relaxes after being stretched.
The wide, elevated rift flanks predicted by the new simulations also appear in images captured by the Magellan probe during its 1990’s mission. The similarities between the modeled structures and the observed landscape strengthen the case that some of these rifts formed relatively recently.
By combining the simulation results with spacecraft observations, the researchers conclude that Venus has a more active and dynamic interior than previously assumed.
“The results help us to better assess the tectonic activity on Venus,” says Gerya.
Guiding Future Venus Missions
The model could help scientists identify regions where geological activity may still be taking place. Those areas could become priority targets for future missions seeking signs of active tectonics or volcanism.
The findings may also improve scientists’ understanding of how rocky planets develop and evolve. The researchers hope the work will eventually provide clues that make it easier to detect and study rocky exoplanets beyond the solar system.
New Missions Will Explore Venus
Scientific interest in Venus is growing as NASA and ESA prepare several missions to investigate Earth’s neighboring planet.
ETH geophysics professors Paul Tackley and Taras Gerya, together with their collaborators, are contributing to ESA’s EnVision mission. Their teams are developing instruments that the Venus orbiter will use to examine the planet’s surface.
EnVision is scheduled to launch in the early 2030s. The mission will study Venus in much greater detail, examining everything from the planet’s core to its upper atmosphere.
