Behavior of Loki Patera, Io revealed through laboratory and mathematical modeling

Paterae are the most abundant volcanic features on Io. An Ionian patera is a depression that is morphologically similar to terrestrial basaltic collapse calderas. Loki Patera is a horseshoe-shaped depression with a maximum width of 200 km, and it contains an 'island' of bright material. Loki Patera is known for experiencing periodic brightening events that occur every 540 days and can emit ≤ 15% of Io's total global heat flux. Two main hypotheses have been proposed for what Loki Patera could be: (1) actively overturning on a lava lake; or (2) succession of lava flows. The focus of this study is to test the actively overturning lava lake theory. I present results from numerical and laboratory modeling to constrain the behavior of Loki Patera. Both corn syrup and polyethylene glycol 600 (PEG) were used as analog lavas in the lab. The results from the mathematical modeling suggests that it is possible for a crustal overturn to produce heat flux values similar to those calculated by thermal instruments here on Earth. The models also do not determine definitively whether Loki Patera is a lava lake or a succession of lava flows. Local subduction of solidified crust was observed in PEG simulations, adding support for the lava lake theory. The thermal data from the corn syrup models have similar thermal signatures as those observed in Galileo Near Infrared Mapping Spectrometer (NIMS) and the Photopolarimeter-Radiometer (PPR) helping to support the hypothesis of a lava lake.