Can a Combination of Convective and Magmatic Heat Transport in the Mantle Explain Io's Volcanic Pattern?

Abstract

Tidal dissipation makes Jupiter's moon Io the most volcanically active body in the solar system. Most of the heat generated in the interior is lost through volcanic activity. In this study, we aim to answer the questions: Can convection and melt migration in the mantle explain the spatial characteristics of Io's observed volcanic pattern? And, if so, what constraints does this place on the viscosity and thickness of the convective layer? We examine three different spatial characteristics of Io's volcanic activity: (i) The presence of global volcanism, (ii) the presence of large-scale variations in Io's volcanic activity, and (iii) the number of Io's volcanic systems. Our study relies on the assumptions that melt in the mantle controls Io's global volcanism, that the large-scale variations of Io's volcanic activity are caused by nonuniform tidal heating, and that the spatial density of volcanoes correlates with the spatial density of convective anomalies in the mantle. The results show that the observed small and large-scale characteristics of Io's volcanic pattern can be explained by sublithospheric anomalies influenced and caused by convective flow. Solutions that allow for active volcanism and Io's specific large-scale variations in volcanic activity range from a thick mantle of a high viscosity ((Formula presented.) Pa s) to a thin asthenosphere of a low viscosity ((Formula presented.) Pa s). Provided that Io's volcanoes are induced by convective anomalies in the mantle, we find that more than 80% of Io's internal heat is transported by magmatic processes and that Io's upper mantle needs to be thicker than 50 km.