Venus may lack the plate tectonics that are responsible for most earthquakes and volcanic eruptions on Earth. However, it is undisputed that the planet closest to Earth is also volcanically active: The more than 1000 Venusian volcanic craters that can be seen on radar images are clear evidence of this. Some of these volcanoes may also have been active in the recent past: this is indicated by the coronas, wreath-like structures. Now two researchers even want to have found evidence that a volcano has recently erupted on Venus. .
According to current models and theories of their formation, active volcanoes on Venus are not unthinkable: it is possible that the planet is still heated from the inside by the decay of radioactive elements.The liquid mantle could make its way to the surface in some places, the hot material could be pushed through the planet’s crust. This also happens on Earth beyond the places where the plates collide or new landmass is formed: The island chain of Hawaii was created in this way.
They found what they were looking for in the Alto Regio region, where Maat Mons is the highest volcano on Venus. It is about eight kilometres high and surrounded by several smaller craters and vents. There they identified a volcanic vent that had grown larger between two images in February 1991 and October 1991: its extent was initially 2.2 Square kilometers and was circular, so it appeared in the later photograph irregularly shaped with a size of about four square kilometers.Further changes on the surface are interpreted by the researchers as a possible lava flow.
However, there are several possibilities why a volcanic vent becomes larger: either because magma has escaped or because an inner magma chamber has flowed off and the vent has partially collapsed. Also, the lava flow identified by the researchers could have been created by such an event – then not the volcano in which they observed the changes would have erupted, but another, which was not visible on the images due to the observational geometry of the probe.
In general, the observation geometry limits the informative value of the observations somewhat: While on the first image the Magellan probe was looking eastwards, on the second image it was oriented to the west. Therefore, the lava flow may not have been the result of a volcanic eruption, but only a result of the different viewing angles: «In the images from the second observation cycle, volcanic lava flows can be seen below the vent.However, we cannot rule out that they were already present in the first cycle due to the different observational geometry, but were invisible,» the authors write.
However, the researchers are certain that the shape of the vent changed between the months of February 1991 and October 1991, and interpret this as a sign of continued volcanic activity on Venus. This would make the planet, also known as the»hellball»because of its extreme surface temperatures, more interesting for research in one fell swoop. How convenient that three missions are currently being planned, the aim of which is, among other things, to investigate more closely what the situation is with volcanism on Venus.
Source — https://www.spektrum.de/news/planetenforschung-vulkanausbruch-auf-der-venus-entdeckt/2120352