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Volcanoes cover nearly the entire surface of Venus

Planetary scientists at Washington University in St. Louis, Paul Byrne and Rebecca Hahn, have compiled the most comprehensive map of all volcanic edifices on Venus, with a database of 85,000 volcanoes using radar imagery from NASA’s Magellan mission. According to the experts, this is a critical breakthrough in the understanding of the volcanic properties of the planet.

“This paper provides the most comprehensive map of all volcanic edifices on Venus ever compiled. It provides researchers with an enormously valuable database for understanding volcanism on that planet – a key planetary process, but for Venus is something about which we know very little, even though it’s a world about the same size as our own,” said Byrne.

The new database will enable scientists to think about where to search for evidence of recent geological activity, either by trawling through the decades-old Magellan data or by analyzing future data and comparing it with Magellan data. 

The study includes detailed analyses of where volcanoes are, where and how they’re clustered, and how their spatial distributions compare with geophysical properties of the planet such as crustal thickness. According to Hahn, the volcano dataset is hosted at Washington University and is publicly available for other scientists to use. 

“We’ve already heard from colleagues that they’ve downloaded the data and are starting to analyze it – which is exactly what we want,” said Byrne. “Other people will come up with questions we haven’t, about volcano shape, size, distribution, timing of activity in different parts of the planet, you name it. I’m excited to see what they can figure out with the new database!”

The scientists found relatively fewer volcanoes in the 20-100 km diameter range, which they believe may be a function of magma availability and eruption rate. 

The experts also wanted to take a closer look at smaller volcanoes on Venus – those less than three miles across that have been overlooked by previous volcano hunters. Hahn says that they represent about 99 percent of her dataset. “We looked at their distribution using different spatial statistics to figure out whether the volcanoes are clustered around other structures on Venus, or if they’re grouped in certain areas.”

Although there are volcanoes across almost the entire surface of Venus, Hahn believes there are hundreds of thousands of additional geologic features that have some volcanic properties lurking on the surface of Venus, too small to be picked up.

“A volcano one kilometer in diameter in the Magellan data would be seven pixels across, which is really hard to see,” explained Hahn. “But with improved resolution, we could be able to resolve those structures.” 

Future missions to Venus in the 2030s by NASA and the European Space Agency are set to acquire high-resolution radar images of the surface that will help scientists search for these smaller volcanoes.

“This is one of the most exciting discoveries we’ve made for Venus – with data that are decades old! But there are still a huge number of questions we have for Venus that we can’t answer, for which we have to get into the clouds and onto the surface. We’re just getting started,” said Byrne.

The study is published in the Journal of Geophysical Research Planets.

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