Spatial distribution of Io's volcanic activity from near-IR adaptive optics observations on 100 nights in 2013-2015

The preferential occurrence of bright, violent eruptions at higher latitudes supports the idea that a deeper magma source supplies these events, as has been previously hypothesized. The monotonic eastward progression of bright eruptions at southern latitudes from 300° to 200°W also suggests a possible eruption triggering mechanism operating across distances of ∼500 km. A comparison to tidal heating models finds a good correspondence between recent models incorporating a partially-fluid interior (Tyler et al. [2015] Astrophys. J., 218-222). and hot spots in the leading hemisphere as well as persistent hot spots. However, hot spots on the trailing hemisphere and bright eruptions do not match these models well, corresponding better to standard deep-mantle heating models (Segatz et al. [1988] Icarus, 75, 187-206) although this match is still imperfect.