Juno data proves volcanism on Io involves numerous lava lakes
A global map of Io’s lava lakes. Click for original figure.
Based on data and imagery produced by the Jupiter orbiter Juno as it made a series of fly-bys of the moon Io from 2022 to 2024, scientists have now mapped at least 40 lava lakes amid the numerous volcanoes on the planet. The map above, figure 2 of the paper, shows their location and approximate relative size across Io’s surface. From the paper’s abstract:
Recent observations from the Juno spacecraft have revealed at least 40 lava lakes on Io, one of Jupiter’s moons, using the JIRAM (Jovian InfraRed Auroral Mapper) imager. Most of the large depressions on Io, known as paterae, show signs of heat, indicating that lava lakes are common. The lava lakes vary in size from 10 to 100 km in diameter and have a thin crust, about 5–10 m thick, that appears to be a few years old. The heat observed mainly comes from the larger crust, not the small exposed lava, so it is hard to measure the total heat output from just the thermal data. Additionally, eight of these lava lakes are new discoveries and were not previously known as active hotspots.
One aspect of these lakes found repeatedly in this new data is that their lava appears to rise and fall as a unit, as if the lake’s floor bed acts like a huge piston pushing the whole lake up and down from below, rather than lava entering in or draining out from a central vent. This conclusion appears to settle the debate between these models for explaining why the lava almost never rises high enough to pour out from the lake. Instead, the lakes themselves appear to be stable features, not volcanic calderas from which lava flows to build a mountain.
