A Global Survey of Gravitationally Deformed Volcanoes on Venus

Abstract

AbstractGravitational instabilities can develop at volcanoes of any size and in any geological setting and can lead to various types of volcano deformation, ranging from small‐scale landslides on the flanks of the edifice to large, deep‐seated sector collapses. As volcanoes grow, they impose an increasing load on the underlying basement, which can result in styles of gravitational deformation where the edifice sags or spreads outward under its own weight. In this study, we utilize our previously developed global catalog of volcanoes on Venus to analyze a subset of edifices that appears to have undergone gravitational deformation. We identify 162 volcanoes that display morphological evidence for gravitational deformation and classify them into four main categories based on associated deformational structures: landsliding, sector collapse, spreading, and sagging. Landsliding of volcano flanks or full sector collapse are the most common and geographically widespread deformational styles on Venus, and account for ∼64% of our data set. Edifices exhibiting structures linked to volcano spreading and sagging are relatively rare; nonetheless, we note for the first time on Venus the presence on a shield volcano of flank terraces, structures linked to sagging. We find that deformed volcanoes are distributed globally, are found at a range of elevations, are spatially proximal to a variety of tectonic structures, and are associated with various crustal thickness values, which together suggest that there are numerous drivers of volcano deformation on Venus.