Venus’s Volcanoes Live

A new analysis of Venus’s surface reveals that between 1990 and 1992, kilometer-scale lava flows appeared in two volcanic regions on the planet. Davide Sulcanese (International Research School of Planetary Sciences, Gabriele d’Annunzio University, Italy) and colleagues report the discovery May 27th in Nature Astronomy.

Venus is the proverbial hellscape, its surface a vast landscape of ancient lava flows that lies smothered beneath a carbon-dioxide atmosphere so thick, the temperature is that of a self-cleaning oven.

This planet-wide outpouring of lava appears to have happened in the last few hundred million years or so. The cataclysm may have even poisoned the planet’s skies, belching volcanic gases into the air that caused temperatures to spike and water to evaporate away.

Scientists have found signs that volcanism continues today on a smaller scale, ranging from upticks of sulfur dioxide in the atmosphere to hotspots on the ground. A breakthrough came last year, when researchers discovered that a vent on the slopes of the volcano Maat Mons had become shallower and changed its shape over the course of eight months, presumably due to eruption-spurred collapse. The collapse came with hints of accompanying lava flows, but these were inconclusive.

Now, Sulcanese and his colleagues have found unambiguous evidence for two sets of flows in archival data from NASA’s Magellan spacecraft.

Magellan mapped almost all of Venus’s surface with radar during its four-year mission in the 1990s; a subset of areas it imaged more than once, and an even smaller subset were re-imaged from similar viewing angles. The Italian team focused on the approximately 16% of surface covered by radar images taken with similar left-looking perspectives.

The researchers found two sets of sinuous and fan-shaped features that appeared between different mappings. One lies on the western flank of the shield volcano Sif Mons, the other a quarter of the way around the planet in western Niobe Planitia, a fairly flat region with numerous volcanoes.

The features flow around obstacles and down the gently sloping ground, the tilt revealed by other Magellan observations. They extend for several kilometers to several tens of kilometers, comparable to basaltic flows in Hawai‘i. “Therefore, the Venusian flows we observed are comparable in size to some of the more extensive flows on Earth,” Sulcanese says.

“I think we’d be hard pressed to find many scientists who didn’t think Venus had ongoing volcanism before,” says Paul Byrne (Washington University in St. Louis), who wasn’t involved with the study. “But it’s one thing to expect something and quite another to actually have evidence for it. Now, with this new discovery, I think we can confidently say that Venus is actively volcanic in the present.”

The flows are radar-bright, indicating they’re rougher than their surroundings. This might be because they’re young and haven’t been around long enough to be eroded, or perhaps they’re a rougher type of lava and lie on top of an older, smoother type, like pahoehoe, Sulcanese says.

Based on the potential volume of the flows and a rough estimate of how many eruptions might occur on Venus — extrapolated from Earth and scaled to Venus’s mass and surface area — the team suggests that volcanism might be as active today on Venus as it is on Earth.

Reference: D. Sulcanese et al. “Evidence of Ongoing Volcanic Activity on Venus Revealed by Magellan Radar.” Nature Astronomy. May 27, 2024.

Editor's note: The original version of this story incorrectly translated Università G. d'Annunzio as Gabriel of the Annunciation University. The university is in fact named for the literary and military figure Gabriele D'Annunzio.