Spatial distribution of volcanoes on Io: implications for tidal heating and magma ascent

摘要: Abstract Extreme volcanism on Io results from tidal heating, but its dissipation mechanisms and magma ascent processes are poorly constrained. Here we analyze the distribution of volcanic hotspots paterae identified within first 1:15,000,000-scale global geologic map to characterize their patterns spatial organization. Ionian correspond locations positive thermal anomalies that have been detected since 1979, whereas caldera-like volcano-tectonic depressions record activity over a longer period time (up ∼1 million years). Some (∼20%) patera floor units associated with active hotspots, majority appeared be extinct or dormant at observation. Volcano distributions useful for testing interior models because relative strength heating in asthenosphere deep-mantle greatly affect expected surface heat flux. We examine centers using nearest neighbor (NN) statistics distance-based clustering. Nearest analysis reveals (i.e., sites volcanism) globally random, closer equator, they uniform more widely spaced than random model would predict). This suggests scavenging around systems near-equatorial region may drive apart, vigorous mantle convection and/or reduce flux variations promote randomness scale. In contrast NN tend clustered, which implies multiple eruptive form association most systems. Generalized paterae, represent systems, uniformly distributed, except northern regions, where is random. interact one another repel, high latitudes, appear independently. Distance-based clustering support dominant role asthenospheric Io, show 30–60° eastward offset volcano concentrations predicted maximum along axis. imply faster synchronous rotation, lateral advection Io's prior eruption, state stress controls ascent, missing component existing models, such as effects fluid tides generated extensive layer interconnected partial melt.