The earthquake that helped us decipher the interior of Mars

Last December 24, 2021probe in sight discovered in Mars pretty strong tremor magnitude 4. If this were on Earth, perhaps we would think that this is the result of millions of children asking for a bonus and jumping around playing the tambourine. Okay, that wouldn’t be too bad either; but equally on Mars it would be impossible. There was only one initially plausible option for earthquake: meteorite impact.

In fact, since InSight reached Mars in 2018, seismograph that is, among their instruments they managed to find about 1300 earthquakes. Or rather, marsquakes. But there was only one comparable to this. happened on September 18 2021 and it was believed that this could be associated with a meteorite, but until another similar event occurred, the scientists of the project did not dare to try to confirm it.

Now, thanks to two studies published in The sciencewe know that his suspicions were correct and that the earthquakes were caused meteorite impact. But we also know much more about the interior of Mars thanks to the study of the waves that were transmitted after the collision. In fact, surface seismic waves were first studied not on Earth, but on another planet.

Two meteorites on Mars

The first study just published is based on observations Martian Reconnaissance Orbiter; a probe that, as the name suggests, orbits the red planet in search of data of interest. With his help, they managed to find two craters that corresponded to the place where seismic probes originated.

They were both big. 130 meters in diameter in September and 150 meters for December. His discovery served as confirmation of the origin of the earthquake. But it remained to find out what information could be extracted from it. And this is what is seen in the second study.

In it they analyze surface wave behavior and they conclude that perhaps the crust of Mars is denser than previously thought. If so, the current understanding of how the planet came into being will be changed. In addition, the current idea that said bark is divided into two parts is being questioned.

This idea stems from the fact that the topography of its two hemispheres is very diverse. They are mostly visible in the north. volcanic lowlands, which may have been covered by the ocean in the past. On the other hand, in the south, high mountain plateaus are distinguished, covered precisely with meteorite craters. This suggests that there is some kind of duality within him too, but this is not the case, judging by the way seismic waves propagate.