37 active volcanoes found on Venus, scientists say this suggests planet's interior is still 'churning'
Scientists have identified 37 recently active volcanic structures on Venus, which provides some of the best evidence yet that Venus is still a geologically active planet.
Researchers have known for some time that Venus has a "younger surface than planets like Mars and Mercury, which have cold interiors". Evidence of a warm interior and geologic activity dots the surface of the planet in the form of ring-like structures known as coronae, which form when plumes of hot material deep inside the planet rise through the mantle layer and crust. This is similar to the way mantle plumes formed the volcanic Hawaiian Islands.
According to the research team, the "active coronae" on Venus are clustered in a handful of locations, which suggests areas where the planet is most active, providing clues to the workings of the planet's interior. These results may help identify target areas where geologic instruments should be placed on future missions to Venus, such as Europe's EnVision that is scheduled to launch in 2032, according to researchers from the University of Maryland and the Institute of Geophysics at ETH Zurich, Switzerland.
"This is the first time we are able to point to specific structures and say, 'Look, this is not an ancient volcano but one that is active today, dormant perhaps, but not dead.' This study significantly changes the view of Venus from a mostly inactive planet to one whose interior is still churning and can feed many active volcanoes," says co-author of the study Laurent Montési, a professor of geology at the University of Maryland, in the analysis published in the journal Nature Geoscience.
Previously, it was thought that the coronae on Venus were probably signs of ancient activity and that Venus had cooled enough to slow geological activity in the planet's interior and harden the crust so much that any warm material from deep inside would not be able to puncture through. Besides, the exact processes by which mantle plumes formed coronae on Venus and the reasons for variation among coronae have been matters for debate among scientists, say experts.
In the current analysis, the authors used "numerical models of thermo-mechanic activity beneath the surface of Venus to create high-resolution, 3D simulations of coronae formation". The simulations provide a more detailed view of the process than ever before, says the study, which has been supported by NASA and the Swiss National Science Foundation.
The results from the analysis helped the researchers identify features that are present only in recently active coronae. The team was then able to match those features to those observed on the surface of Venus, revealing that some of the variations in coronae across the planet represent different stages of geological development. The study provides the first evidence that coronae on Venus are still evolving, indicating that the planet is churning inside, says the study.
"The improved degree of realism in these models over previous studies makes it possible to identify several stages in corona evolution and define diagnostic geological features present only at currently active coronae. We can tell that at least 37 coronae have been very recently active," says Montési.