Magma still causes earthquakes on the red planet

Most of the seismic activity detected on the planet Mars by the InSight mission shows that the Red Planet “is not that dead”, with magma movements identical to those at work on Earth or Venus.

The images of the desolate surface of Mars obtained by the probes which have landed there are misleading.

Because even if “the main volcanic activity of the planet dates back 3.5 billion years, it is not that dead”, comments Clément Perrin, physicist at the laboratory of planetology and geosciences of Nantes University.

Mars is even very much alive, according to the periodic tremors of earthquakes recorded since February 2019 by the InSight mission. Its seismometer, a high-precision instrument developed by the National Center for Space Studies (CNES), is placed more than 1,200 km from the Cerberus Fossae (Cerberus Fossae).

The latter is one “of the youngest areas on Mars, around 10 million years old”, explains Mr. Perrin, “with open fractures, which are associated with volcanic activities”, explains Mr. Perrin who co-signs in Nature the study conducted by Simon Stähler, from the Zurich Polytechnic School.

These pits, “real canyons, several hundred km long, up to one kilometer wide and one kilometer deep”, are of interest to researchers in more ways than one. A recent geological study has shown, with the help of images taken by a probe orbiting Mars, the remains of volcanic activity dated from 50,000 to 200,000 years. In other words, something “quite young, what you can have with dormant volcanoes in France”, says Mr. Perrin.

The InSight mission brings a new look to these data, and the confirmation, with its seismic study, that the planet is very much alive, even if we do not see any volcano in activity.
“Before leaving for Mars with InSight, we said to ourselves that it was a bit at the end of its life, with a very active nucleus”, says the physicist. The researchers expected to find a star shaken by “small earthquakes coming from everywhere”, a sign that it is slowly contracting as it cools. As the Moon or Mercury do today.

But the InSight seismometer recorded something else, “mostly a source showing internal planetary activity”. The machine detected earthquakes in the Fosses de Cerbère area that scientists attribute to circulations of magma, molten rock, in the crust of Mars at depths ranging from 15 to 50 km.

“Although we still have a lot to learn, the evidence for potential magma on Mars is intriguing,” according to Anna Mittelholz, post-doctoral researcher at the Polytechnique de Lausanne, and quoted by the University.

For his part, Pr. Stähler wonders if “what we see are the last remnants of activity of a formerly volcanic region or if the magma is moving east and a new eruption zone “.

To get the answer, you will quickly need a replacement for the InSight mission, whose seismometer should stop working in the coming months. Its solar panels, clogged with dust, will no longer provide enough electricity to operate.