Assessing the Evidence for Active Volcanism on Venus: Current Limitations and Prospects for Future Investigations

One of the biggest unknowns about Venus is how volcanically active it is today. Venus has a similar size and density to Earth, suggesting it may have a comparable composition, and therefore it is expected to be volcanically active; however, exploring Venus and confirming current volcanic activity is difficult because of the thick omnipresent optically opaque clouds that hamper traditional observations of the lower atmosphere and surface. Further, surface conditions make long-lived missions challenging. Despite the difficulty, there have been tantalizing hints of currently active or very recent volcanism. Here, we review what is known about active volcanism, point out gaps in knowledge to be addressed, and highlight techniques and approaches that need to be developed before the new decade of Venus exploration. It is crucial to constrain the activity and rate of volcanism today and through time to begin to understand the geodynamic state of the planet.

We find that the combination of all evidence strongly indicates that Venus is volcanically active today. The best evidence for active volcanism comes from combining data sets and approaches – specifically at Idunn Mons, Maat Mons, and Aramaiti Corona – in contrast to those from a single study or data set alone. Considering the evidence for activity, observations do not favor so-called “catastrophic” models of resurfacing, instead they are better represented by ongoing regional scale events. To reliably detect and characterize active or recent effusive basaltic volcanism new missions must collect high-resolution imaging, repeat observations, radar polarimetry, evidence of outgassing, and high-resolution topographical data that provide insights into surface changes over time. The ability to capture and interpret these data is vital for understanding Venus’s geological activity, particularly in regions where volcanic processes are suspected to be ongoing.