Venus is home to many thousands of volcanic landforms that range in size from much less than 5 km to well over 100 km in diameter. Volcanism is a major, widespread process on Venus and is a principal expression of the planet’s secular loss of interior heat.
With the Magellan SAR (synthetic-aperture radar) FMAP (full-resolution radar map) left- and right-look global mosaics at 75 meter-per-pixel resolution, WashU planetary scientists Paul Byrne and Rebecca Hahn have developed a global catalog of volcanoes on Venus. This map of 85,000 volcanoes on Venus helps locate the next active lava flow.
Byrne said, “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.”
Hahn, a graduate student in earth and planetary sciences at Washington University first author of the new paper, said, “We came up with this idea of putting together a global catalog because no one’s done it at this scale before. It was tedious, but I had experience using ArcGIS software, which I used to build the map. That tool wasn’t available when these data first became available in the ’90s.”
“This new database will enable scientists to think about where else to search for evidence of recent geological activity. We can do it either by trawling through the decades-old Magellan data (as the new Science paper did) or by analyzing future data and comparing it with Magellan data.”
This new study includes detailed analyses of where volcanoes are, where and how they’re clustered, and how their spatial distributions compare with the planet’s geophysical properties, such as crustal thickness. It also offers detailed insights into Venus’ volcanic properties — and perhaps of any world’s volcanism so far.
The scientists discovered significantly fewer volcanoes in the 20-100 km diameter range, despite the fact that there are volcanoes on practically the whole surface of Venus. They hypothesize that this may be due to the availability of magma and the eruption rate.
Byrne and Hahn also wanted to take a closer look at smaller volcanoes on Venus, those less than 3 miles across that have been overlooked by previous volcano hunters.
Hahn said, “They’re the most common volcanic feature on the planet: they represent about 99% of my dataset. We looked at their distribution using different spatial statistics to determine whether the volcanoes are clustered around other structures on Venus or if they’re grouped in certain areas.”
Byrne said, “This is one of the most exciting discoveries we’ve made for Venus — with data that are decades old! But there are still many questions we have for Venus that we can’t answer, for which we have to get into the clouds and onto the surface.”