Hellish Venus is home to some of the strangest volcanoes in the Solar System — giant flattened domes resembling enormous pancakes. For a long time, scientists believed that these “pancake domes” were formed solely by extremely thick lava that flowed slowly. However, a new study has revealed an unexpected accomplice: the curved crust of the planet itself.

The study, published in the Journal of Geophysical Research, focused on the giant dome of Narina Tholus, which has a diameter of about 145 km. Using old but valuable radar data from NASA’s Magellan mission, the team constructed a virtual model of the dome. Their goal was to understand what kind of lava and what properties of Venus’ crust could have led to the emergence of such a unique “pancake” shape.
The results were unexpected. Simulation showed that thick lava alone is not enough to explain the flattened shape of the domes with steep slopes. The planet’s crust played a key role. Our models clearly demonstrate that the curvature of the crust significantly influences the final shape of the dome. The stronger the bend, the flatter the summit becomes and the steeper the slopes are,” the researchers note.
Just as a soft surface bends under a heavy object, Venus’ crust is capable of forming depressions and deforming under the weight of extremely thick flowing lava. When scientists included this bend in the lithosphere in their model and simulated lava flow along it, the molten rock stopped spreading freely. Instead, it began to accumulate in the center, forming a characteristic flat top and steep sides — just like the real “pancake domes” on Venus. This model also successfully explained the presence of crustal bulges around some domes that had been recorded earlier.

But not all lava is capable of forming such shapes. The model required extraordinary characteristics: the lava had to be very dense and incredibly viscous. Only such physical characteristics could reproduce the shape of Narina Tholus. Researchers believe that the process of forming one such enormous “pancake” could have taken hundreds of thousands of Earth years.
Although the model is based on the analysis of only one dome, it offers a revolutionary view of Venus’ geology. Previously, the main focus was on the properties of the lava, but now the curvature of the crust plays an equal role in shaping these amazing landforms.
The next step will be to test this theory on thousands of other volcanic domes on Venus. The hope lies in future space missions, such as NASA VERITAS and DAVINCI, which will be able to provide much more detailed topographical information about the planet’s surface.
Earlier, we reported on how an active volcano was discovered on Venus.
According to livescience.com