Mars tremors suggest volcanoes are still shaping the Red Planet’s surface

New research suggests that volcanic activity still plays an active role in shaping the surface of Mars.

Since 2018, when NASA’s InSight mission deployed the SEIS seismometer to the surface of Mars, seismologists and geophysicists have listened to seismic pulses from more than 1,300 Marsquakes.

Again and again, researchers have recorded smaller and larger March tremors. A detailed analysis of the location and spectral character of the earthquakes revealed a surprise.

With epicenters originating from the vicinity of Cerberus Fossae – a region made up of a series of fissures, or graben – these earthquakes tell the new story of the surface.

Mars tremors indicate recent volcanic activity

Researchers analyzed a group of more than 20 recent earthquakes that originated in the Cerberus Fossae graben system. From the seismic data, the scientists concluded that the low frequency earthquakes indicate a potentially hot source which could be explained by the current molten lava, i.e. magma at this depth, and the activity volcano on Mars.

Specifically, they found that the earthquakes were mostly in the innermost part of Cerberus Fossae.

When they scanned observational orbital images of the same area, the researchers noticed that the epicenters were located very close to a structure previously described as a “young volcanic fissure”. Darker dust deposits around this fissure are present not only in the prevailing wind direction, but in all directions surrounding the Cerberus Fossae mantle unit.

“The darker tint of the dust signifies geological evidence of more recent volcanic activity – possibly within the past 50,000 years – relatively young, in geological terms,” ​​says Simon Stähler, lead author of the new paper. in Nature. Stähler is a senior scientist working in the seismology and geodynamics group led by Domenico Giardini, professor at the Institute of Geophysics at ETH Zurich.

Dry ice on the polar caps

Exploring Earth’s planetary neighbors is no easy task. Mars is the only planet, other than Earth, on which scientists have rovers, landers, and now even ground-based drones transmitting data. Until now, all other planetary explorations have relied on orbital imagery.

“InSight’s SEIS is the most sensitive seismometer ever installed on another planet,” says Giardini. “This offers geophysicists and seismologists the opportunity to work with current data showing what is happening on Mars today, both on the surface and inside.”

Seismic data, along with orbital images, provide a greater degree of confidence for scientific inferences.

One of our closest terrestrial neighbors, Mars is important for understanding similar geological processes on Earth. The red planet is the only one we know of, so far, whose core is made up of iron, nickel and sulfur that could once have supported a magnetic field.

Topographical evidence also indicates that Mars once contained large bodies of water and possibly a denser atmosphere. Even today, scientists have learned that frozen water, although possibly mostly dry ice, still exists on its polar caps.

“While there is still much to learn, the evidence for potential magma on Mars is intriguing,” says Anna Mittelholz, postdoctoral fellow at ETH Zurich and Harvard University.

Not quite dead yet

Looking at images of the vast, dry, dusty Martian landscape, it’s hard to imagine that around 3.6 billion years ago, Mars was very much alive, at least in a geophysical sense. It spewed volcanic debris long enough to give rise to the region of Tharsis Montes, the largest volcanic system in our solar system, and Olympus Mons, a volcano almost three times higher than Mount Everest.

Earthquakes originating from the nearby Cerberus Fossae – named after a creature from Greek mythology known as the “hellhound of Hades” that guards the underworld – suggest Mars isn’t quite there yet. absolutely dead.

Here, the weight of the volcanic region sinks in and forms parallel grabens (or cracks) that separate the crust of Mars, much like the cracks that appear on top of a cake as it bakes.

According to Stähler, it’s possible that what we’re seeing are the last remnants of this once active volcanic region or that magma is currently moving east toward the next eruption location.

Other co-authors come from ETH Zurich, Harvard University, University of Nantes, CNRS Paris, German Aerospace Center (DLR) in Berlin and Caltech.

Source: ETH Zürich

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