Vulcanism in Mars’s innermost part shaping its surface: Study

PTI

Bern (Switzerland), October 28

Vulcanism or volcanic activity still plays an active role in shaping the Martian surface, scientists said after detecting low-frequency quakes in the planet’s innermost part indicating a potentially warm source comparable to molten lava.

The scientists analysed a cluster of more than 20 recent marsquakes that originated in the Cerberus Fossae graben system, a region consisting of a series of rifts or graben. From the seismic data, they concluded that the low-frequency quakes indicate a potentially warm source that could be explained by present day molten lava—magma at that depth—and volcanic activity on Mars.

Specifically, they found that the quakes are located mostly in the innermost part of Cerberus Fossae—a name for a creature from Greek mythology known as the ‘hell-hound of Hades’ that guards the underworld.

The study, published in Nature Astronomy, was led by ETH Zurich and involved scientists from Harvard University, Nantes Université, CNRS Paris, German Aerospace Center in Berlin, and Caltech.

When they compared seismic data with observational images of the same area, they also discovered darker deposits of dust not only in the dominant direction of the wind, but in multiple directions surrounding the Cerebus Fossae Mantling Unit.

“The darker shade of the dust signifies geological evidence of more recent volcanic activity – perhaps within the past 50,000 years – relatively young, in geological terms,” lead author of the study Simon Staehler explained.

Exploring Earth’s planetary neighbours is no easy task, the scientists said.

Mars is the only planet, other than Earth, in which scientists have ground-based rovers, landers, and now even drones that transmit data.

All other planetary exploration, so far, has relied on orbital imagery, according to the study.

“InSight’s SEIS is the most sensitive seismometer ever installed on another planet. It affords geophysicists and seismologists an opportunity to work with current data showing what is happening on Mars today – both at the surface and in its interior,” said another co-author of the study Domenico Giardini.

The seismic data, along with orbital images, ensures a greater degree of confidence for scientific inferences.

“One of our nearest terrestrial neighbours, Mars is important for understanding similar geological processes on Earth. The red planet is the only one we know of, so far, that has a core composition of iron, nickel, and sulphur that might have once supported a magnetic field,” according to the study.

Topographical evidence also indicates that Mars once held vast expanses 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, the team said.

“While there is much more to learn, the evidence of potential magma on Mars is intriguing,” another researcher in the study Anna Mittelholz said.

Looking at images of the vast dry, dusty Martian landscape, it is difficult to imagine that about 3.6 billion years ago Mars was very much alive, at least in a geophysical sense, the study said.

It spewed volcanic debris for a long enough time to give rise to Tharsis Montes region, the largest volcanic system in our solar system and the Olympus Mons – a volcano nearly three times the elevation of Mount Everest, it said.

The quakes coming from the nearby Cerberus Fossae suggest that Mars is not quite dead yet, the scientists said.

Here the weight of the volcanic region is sinking and forming parallel graben (or rifts) that pull the crust of Mars apart, much like the cracks that appear on the top of a cake while its baking, the study said.

“It is possible that what we are seeing are the last remnants of this once active volcanic region or that the magma is right now moving eastward to the next location of eruption,” Staehler said.