A new study lays the groundwork for detecting volcanic activity on Venus

Spotting volcanic activity on another planet could give scientists insight into what’s going on under the hood. But that’s only if they recognize what they’re looking at.

Recent research led by Ian Flynn, a postdoctoral fellow in the Kenneth P. Dietrich School of Arts and Sciences’ Department of Geology and Environmental Science, aimed to model how lava flows might look on Venus, work that will inform three upcoming missions to the planet from NASA and the European Space Agency. Their paper was published in the Journal of Geophysical Research: Planets.

Understanding volcanism on Venus is more than a passing interest for planetary scientists. Each of those three missions will look for signs of new lava flows, a telltale indication of recent eruptions. The eruptions may have played an important role in shaping the surface and atmosphere of the planet, sometimes called “Earth’s twin” because of the two planets’ similar size and mass.

Geologists have an intimate familiarity with how lava flows on Earth — but it could play by different rules under the conditions on Venus. It might not spread far enough to give an orbiting probe a chance to see it. It might cool off too fast. Any number of changes in its behavior might mean an orbiter might not be able to tell that there is, in fact, active volcanism right under its nose. 

And in terms of temperature, Venus is anything but Earth’s twin. “It’s just so hot on Venus,” Flynn said. “Temperatures hover around 850 degrees Fahrenheit, which is enough to melt lead.”

To determine how lava flows may differ on Venus, Flynn’s team needed a model that reflected those hellish conditions.

"We took a model used on Earth and incrementally adapted it to the environmental conditions on Venus," Flynn said. First, they changed the gravity in the model to match gravity on Venus, then the temperature, and then other atmospheric conditions, including density and composition.

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The team found that lava from an eruption on Venus would flow about 75% farther than from the same eruption on Earth. “Using the model, we determined that we should be able to see and collect data from active lava flows, should an eruption occur,” Flynn said. This finding also considered how the missions will work, factoring in how often probes will orbit the planet as well as the capabilities of their instruments.

Flynn is particularly familiar with the instrumentation on ESA’s EnVision mission, which in collaboration with NASA is aiming for a launch to Venus in the early 2030s. He has been working with a member of the mission’s science team to determine detection thresholds for the probe’s instruments

“If the instruments aren’t calibrated properly to see the lava flow, it doesn’t matter,” Flynn said. “Using this model, we can help to prep the upcoming missions to find evidence of volcanism on Venus.” 

— Brandie Jefferson, photography by NASA/JPL. Ushas Mons, a volcano in the southern hemisphere of Venus is shown in this radar image from NASA Magellan spacecraft. The volcano is marked by numerous bright lava flows and a set of north-south trending fractures.