Infrasound waveguides on Venus enable exploration of explosive volcanism using balloons

On Earth, infrasound can travel vast distances through waveguides formed by changes in the sound speed and wind structure. While propagating, these waves retain valuable information about the source and the propagation medium, making infrasound suitable to monitor explosive events, including from volcanic sources.  

In contrast to Earth, extreme conditions on the surface rule out conventional ground-based sensors for infrasound recording on Venus. A more practical alternative is to use atmospheric balloons equipped with acoustic sensors. Such balloons can be deployed in the middle atmosphere, where conditions allow for longer mission durations.  

However, to explore the existence of prospective explosive volcanism on Venus, such deployments will only be valuable if there exist waveguides to duct the infrasound from these sources to the balloons. But do such waveguides exist? To address this question, we performed an extensive set of wave-propagation simulations to map the global morphology of infrasound ducting on Venus, with the Venus Climate Database as the atmospheric model. We considered volcanic sources and assessed how effectively infrasound is guided to balloon altitudes.  

We find persistent waveguides in both zonal and meridional directions, driven by the strong superrotational and subsolar-to-antisolar winds in the middle and upper atmosphere. We find that these waveguides enable ground-to-balloon propagation, indicating that the conditions are suitable for detecting long-range infrasound. Our discovery strengthens the case for future balloon-based missions to Venus.