Lava Lakes on Io: Crust Age and Implications for Thermal Output

Abstract Recent observations by the JIRAM instrument on board NASA’s Juno spacecraft have confirmed that many of Io’s volcanic hotspots are active lava lakes, characterized by a colder central crust surrounded by a hotter peripheral ring. In this study, we investigate the thermal properties of 30 such lava lakes, providing new constraints on their structure and energy budget. We find that most of the total power from Io’s lava lakes comes from their low-temperature crusts rather than the hotter peripheral rings, suggesting that previous estimates underestimated lava-lake power by up to a factor of 10. Io’s paterae undergo stochastic resurfacing on timescales of roughly a decade, with each lake possibly following its own characteristic cycle. We also explore the relationship between the average temperature of the crust and the evolutionary state of each lake, offering insights into the frequency of resurfacing processes. Finally, we propose an improved assessment of Io’s global thermal output, emphasizing that only full-surface observation of Io with sufficient spatial and spectral resolution can yield realistic values for the moon’s volcanic total heat flux.