Simulations conducted by researchers at ETH Zurich reveal that Venus rift valleys, including Ganis, Dali, and Devana Chasmata, exhibit broad, steep flank uplifts consistent with tectonic extension occurring at rates of three to ten centimetres per year, reshaping understanding of the planet’s internal activity.
Simulating Venusian Tectonic Activity and Rift Dynamics
Planetary scientists long viewed Earth’s sister planet as geologically dormant. However, researchers at ETH Zurich, led by Professor of Geodynamics Taras Gerya and lead author Xi Yang, have developed innovative three-dimensional computer models to study the extensive rift valley systems crisscrossing the Venusian surface. These systems cover roughly eight per cent of the planet through approximately 40,000 kilometres of mapped rifts.
Earlier computer models relied on simplified material assumptions and two-dimensional frameworks. The new high-resolution 3D simulations demonstrate that tectonic rift valleys feature high, broad flanks when the structures are geologically young and either actively moving or recently active. According to the research published in Nature Geoscience, these rifts widen at rates of three to ten centimetres per year under specific thermal and crustal conditions.
The results help us to better assess the tectonic activity on Venus.
Taras Gerya, Department of Earth and Planetary Sciences, ETH Zurich
Durable Topography Preserved Without Rain or Rivers
Unlike Earth, where continuous rain, rivers, glaciers, landslides, and sediment transport constantly erode raised flanks and obscure original valley shapes, Venus lacks surface oceans and liquid water rain. Although sulphuric-acid clouds contain droplets, those droplets evaporate before reaching the parched surface. Geological weathering on Venus is driven primarily by wind, chemical processes, and volcanic burial, making erosion extremely slow.
This lack of rapid water-based erosion allows long-lived topography to retain structural details that Earth quickly erases. When rifting occurs on Venus, fault-bounded blocks subside while adjacent crust rises and flexes, producing elevated shoulders. The computer simulations reveal that these broad flanks flatten rapidly after movement ceases through crustal relaxation. A flank wider than 100 kilometres serves as a primary diagnostic indicator associated with extension that either continues today or ended recently in geological terms.
Evaluating Specific Chasmata Against Experimental Models
The research team compared their numerical experiments with topography sampled at 16-kilometre intervals by NASA’s Magellan probe during its 1990s mission.
- Dali Chasma: Features a median flank width of about 110 kilometres, a steep western side with an offset near five kilometres, and a gentler eastern side.
- Ganis Chasma: Displays a median flank near 160 kilometres and an offset near four kilometres along its steep western side.
- Devana Chasma: Exceeds 180 kilometres in width with steep sides surrounding a flatter valley floor, matching the broad flank signature of young, rapid rifting in the models.
These morphological profiles most closely resembled strong dry-diabase or mafic-granulite crust stretched at rates between three and ten centimetres per year. While the study does not independently measure current movement rates, the structural evidence indicates that parts of Venus may be tearing open today or may have stopped within the past few tens of millions of years—a remarkably brief window on a slowly eroding planet.
The findings carry significant implications for upcoming exploratory campaigns. ETH geophysics professors Paul Tackley and Taras Gerya are participating in the European Space Agency’s EnVision mission, scheduled for launch in the early 2030s, where newly identified active regions will receive close examination from the planet’s core to its upper atmosphere.
