JUPITER – If there were rewards for the most powerful and persistent active volcano in the solar system, the first prize would go straight to Loki Patera who works on Io. One thing is for sure, Jupiter’s moon will never be a holiday destination, even for the most chilly.
Io is one of the four Galilean moons, the closest to the planet. It is also the fourth largest moonin the Solar System. It is distinguished notably by its intense volcanic and magmatic activity. Loki Patera is the largest crater visible on the moon. It is 202 kilometers in diameter and contains a lake partially filled with molten lava covered by a thin solidified crust. These lava lakes are directly connected to a reservoir of magma situated at depth.
Two years ago, researchers took advantage of a rare astronomical event to create a detailed map of this king of volcanoes. They then observed waves of magma bleeding on the surface of the moon. The team of astronomers at the University of California at Berkeley only recently published in the journal Nature its measurements of the geological phenomenon carried out using a sequence of thermal images taken in March 2015 by the Large binocular telescope installed in Arizona. These observations were made possible thanks to Europe, another moon of Jupiter this time covered with ice. By crossing the orbit of Io, thanks to its frozen water coating, Europe has not reflected infrared wavelengths, allowing researchers to distinguish between temperature differences on the surface of Io.
This Galilean “eclipse” combined with advanced optical technology have allowed scientists to trace hot spots on the surface of the moon. Concerning Loki Patera, previous studies had described an active volcano surrounded by a melting-filled depression that resurfaced every 400-600 days, causing lava waves to progress around the basin at a speed of about one to two kilometers per day. This then raised an interesting question: where does this fresh lava come from?
As the molten rock cools on the surface, it then increases in density. Because solidified lava is denser than magma, these rocks can sink over time, causing an increase in the thermal emission of the volcano. Each collapse creates a creeping magma wave. ” In this scenario, parts of fresh ridge fall, exposing the glowing magma below and causing a glow in the infrared, ” says lead researcher Katherine de Kleer of the University of California at Berkeley. Differences in temperature revealed a magma wave starting from the northwest corner of the surrounding basin and moving gradually clockwise while a more recent wave moved eastward in the opposite direction .
More observations will provide researchers with more details on the “plumbing” of Loki Patera. However, the team will have to wait until 2021 for Europe to be back in line with Io.