‘Comprehensive’ map of volcanoes on Venus – 85,000 in all – ScienceDaily

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Intrigued by reports of recent volcanic eruptions on Venus? WASHU planetary scientists Paul Byrne and Rebecca Hahn want their new map of 85,000 volcanoes on Venus to be used to help locate the next active lava flow.

Their study was published online ahead of print in JGR Planets.

“This paper presents the most comprehensive map of all volcanic edifices ever assembled on Venus,” said Byrne, associate professor of Earth and Planetary Sciences in Arts & Sciences at Washington University in St. Louis. “It provides researchers with a very valuable database for understanding volcanic activity on this planet – a major planetary process, but for Venus something we know very little about, even though it is a world about the same size as ours.”

Byrne and Hahn used radar images from NASA’s Magellan mission to Venus to classify volcanoes across Venus on a global scale. Their resulting database contains 85,000 volcanoes, about 99% of which are less than 3 miles (5 km) in diameter.

“Since NASA’s Magellan mission in the 1990s, we’ve had many major questions about the geology of Venus, including its volcanic properties,” Byrne said. “But with the recent discovery of active volcanoes on Venus, understanding where the volcanoes are concentrated on the planet, how many there are, how big they are, etc. becomes even more important — especially as we have new data for Venus in the coming years.”

“We came up with the idea to compile a global catalog because no one had done it on this scale before,” said Han, a graduate student in Earth and Planetary Sciences at the University of Washington and first author of the new paper. “It was boring, but I had experience with ArcGIS, which is what I used to create the map. This tool wasn’t available when this data first became available in the 1990s.

“People at the time were hand-drawing circles around volcanoes, when I could have done that on my computer.”

“This new database will enable scientists to think of where else to look for evidence of recent geological activity,” said Byrne, a faculty fellow at the university’s McDonnell Space Science Center. “We can do this either by digging into the old Magellan data (as the new scientific paper did) or by analyzing future data and comparing it to the Magellan data.”

Berne and Hahn’s new study includes detailed analyzes of where the volcanoes are, where and how they cluster, and how their spatial distributions compare to the planet’s geophysical characteristics such as crustal thickness.

Taken together, this work provides the most comprehensive understanding of the volcanic properties of Venus – and perhaps of any volcanic activity in the world to date.

This is because, although we know a lot about volcanoes on Earth, it’s still possible that a lot of them could be discovered under the oceans. Because it has no oceans of its own, the entire surface of Venus can be seen using Magellan’s radar images.

Although there are volcanoes across almost the entire surface of Venus, scientists have found relatively fewer volcanoes within a diameter range of 20 to 100 kilometers, which could be a result of magma availability and eruption rate, they estimate.

Byrne and Hahn also wanted to get a closer look at the smaller volcanoes on Venus, those less than 3 miles wide that previous volcano hunters had overlooked.

“It’s the most common volcanic feature on the planet: it’s about 99% of my data set,” Hahn said. “We looked at their distribution using different spatial statistics to see if the volcanoes cluster around other structures on Venus, or if they cluster in certain regions.”

The new volcano dataset is hosted at the University of Washington and is publicly available for the use of other scientists.

“We’ve already heard from our colleagues that they’ve downloaded the data and started analyzing it – and that’s exactly what we want,” Byrne said. “Other people will come in with questions that we don’t have, about the shape of the volcano, its size, its distribution, the timing of activity in different parts of the planet, you name it. I’m excited to see what they can find out with the new database!”

And if 85,000 volcanoes on Venus sounds like a lot, Hahn said it’s actually conservative. She believes that there are hundreds of thousands of additional geological features that have some volcanic properties underlying the surface of Venus. It’s too small to capture.

“A diameter of 1 km in the Magellan data would be 7 pixels wide, which is really hard to see,” Hahn said. “But with improved resolution, we can solve those structures.”

And this is exactly the kind of data that future missions to Venus in the 2030s will gain.

“Both NASA and the European Space Agency (ESA) are sending a mission to Venus in the early 2000s to take high-resolution radar images of the surface,” Byrne said. “With these images, we will be able to search for those smaller volcanoes that we expect to be there.

“This is one of the most exciting discoveries we’ve made for Venus – with decades-old data!” Byrne said. “But there are still a great number of questions we have about Venus that we cannot answer, and that we have to get into the clouds and on the surface.

“We’re just getting started,” he said.

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