Magellan data reveals active volcanoes on Venus

Using data from NASA’s Magellan mission, scientists have discovered direct geological evidence of ongoing volcanic activity on the surface of Venus. The study, led by Davide Sulcanese of d’Annunzio University in Pescara, Italy, analyzed lava flows observed in two locations on the planet, revealing that the volcanic activity on Venus could be comparable to that on Earth.

The findings solidify previous predictions about Venus being volcanically active. As Sulcanese stated, “Using these maps as a guide, our results show that Venus may be far more volcanically active than previously thought. By analyzing the lava flows we observed in two locations on the planet, we have discovered that the volcanic activity on Venus could be comparable to that on Earth.”

The first direct evidence of volcanic activity on Venus was discovered in 2023 when a vent near the volcano Maat Mons was seen to change its appearance over time as molten rock from the planet’s interior filled the vent and spilled out onto its slopes.

In the new study, the researchers focused on two volcanoes: Sif Mons, located in the Eistla Regio region, and a volcano in the western part of the Niobe Planitia region. By analyzing backscatter data collected by Magellan in 1990 and 1992, they observed an increase in signal strength along certain paths in later orbits, suggesting the formation of new rock on the surface.

To confirm that the new rock is indeed volcanic, the researchers analyzed altimetry data from Magellan to determine the slope of the topography and locate surface features that lava would need to flow around. As co-author Marco Mastrogiuseppe explained, “We interpret these signals as flows along slopes or volcanic plains that can deviate around obstacles such as shield volcanoes like a fluid. After ruling out other possibilities, we confirmed our best interpretation is that these are new lava flows.”

By comparing the Venusian lava flows to those on Earth, the scientists estimated the following:

• The new rock on Venus is between 3 and 20 meters deep.
• The eruption of the Sif Mons volcano created around 30 square km of rock.
• The eruption of the Niobe Planitia volcano created around 45 square km of rock.

In contrast, the 2022 eruption of the Mauna Loa volcano in Hawaii on Earth produced enough lava flow to fill 100,000 Olympic swimming pools, while the Sif Mons and Niobe Planitia volcanoes could only fill 36,000 and 54,000 pools, respectively.

These discoveries further excite the planetary science community for future missions to Venus, such as NASA’s VERITAS and DAVINCI missions set to launch in the next decade. As JPL’s Suzanne Smrekar, VERITAS’s principal investigator, stated, “These new discoveries of recent volcanic activity on Venus by our international colleagues provide compelling evidence of the kinds of regions we should target with VERITAS when it arrives at Venus. Our spacecraft will have a suite of approaches for identifying surface changes that are far more comprehensive and higher resolution than Magellan images. Evidence for activity, even in the lower-resolution Magellan data, supercharges the potential to revolutionize our understanding of this enigmatic world.”

The Magellan mission was a pioneering endeavor that provided unprecedented insights into the surface geology and volcanic activity on Venus. Launched by NASA in 1989, Magellan was designed to map the entire surface of Venus using synthetic aperture radar (SAR) and measure the planet’s magnetic field.

Magellan carried a powerful radar system that could penetrate the thick, opaque atmosphere of Venus, allowing it to capture high-resolution images of the planet’s surface features. Over the course of its mission, Magellan mapped 98% of Venus’s surface, revealing a wealth of geological features, including mountains, valleys, and vast lava plains.

One of Magellan’s key objectives was to study the volcanic history and potential ongoing activity on Venus. The mission’s SAR data provided detailed images of volcanic features, such as shield volcanoes, lava flows, and caldera complexes, offering insights into the planet’s volcanic past. Magellan’s altimetry data also helped measure the topography of these volcanic structures, providing valuable information about their size, shape, and elevation.

To study potential ongoing volcanic activity, Magellan employed a technique called change detection, which involved comparing radar images of the same region taken at different times. By analyzing the backscatter data, scientists could identify changes in the surface features, which might indicate the presence of fresh lava flows or other volcanic activity.

Magellan’s data collection spanned several Venus cycles, allowing for multiple observations of the same regions over time. This enabled scientists to identify and monitor any changes that occurred, providing crucial evidence for potential active volcanism on the planet.

While Magellan’s primary mission ended in 1994, its data has continued to be a valuable resource for understanding Venus’s geology and volcanic processes. The recent discoveries of ongoing volcanic activity on Venus, as detailed in the study by Davide Sulcanese and colleagues, were made possible by analyzing Magellan’s extensive radar data sets.