Marsquakes could hold tantalizing clues to secrets that lie beneath the Red Planet's mysterious surface

Recording the first such quake on Mars in April this year, NASA's InSight Mission has detected 322 so far. While most are mild, of magnitudes that are barely felt on Earth, a couple of these Marsquakes have been big, up to nearly magnitude 4.


                            Marsquakes could hold tantalizing clues to secrets that lie beneath the Red Planet's mysterious surface
A camera on NASA's InSight Mars lander acquired this image of the area in front of the lander. (NASA/JPL-Caltech)

Mars trembles nearly twice a day. These tremors are the result of marsquakes, a feature that the Red Planet shares with the Earth and the Moon, according to scientists who reported their findings at a meeting of the American Geophysical Union in San Francisco, California.

These findings are the result of NASA's InSight Mission that landed on Mars last year. Since its arrival, the lander is keeping its ear to the ground, listening in to the sounds during marsquakes. Recording the first such quake in April this year, the InSight has detected 322 Marsquake until now, say scientists.

The rate of quakes has been increasing, from a few sporadic tremors reported after InSight landed to the current pace of two a day, says Bruce Banerdt, a geophysicist at the Jet Propulsion Laboratory in Pasadena, California, and InSight’s principal investigator. Scientists are trying to understand what is driving this. 

While most Marsquakes are mild, of magnitudes that are barely felt on Earth, a couple of these quakes have been big — up to nearly magnitude 4. Two of them were traced to a region called Cerberus Fossae, which lies about 1,600 kilometres east of InSight. Scientists speculate that the quakes are a result of built-up stress on fractures along the Martian crust. This stress may have been released in a marsquake, they say.

Why study marsquakes?

Studying marsquakes will reveal the secrets that lie hidden beneath Mars' surface. So far, scientists know that unlike Earth, Mars' quakes are not caused by tectonic plates: solid rocks that a part of Earth's interiors. Instead, they could be triggered by slow cooling of the planet over time, which, in turn causes fractures to develop on its surface. 

InSight is designed to drill through the surface 5 meters deep and place the instrument, the heat probe, within Mars’ crust. (NASA, JPL-Caltech)

To determine the rate at which the planet is cooling, the InSight lander comes armed with a heat probe. For this, the instrument will have to drill through the surface 5 meters deep into Mars' crust.

But, in October, the digging process hit a snag. “The hammer hammers it down, but it just bounces right back up again,” Banerdt told Eos. The reason, say scientists, is the Martian soil around InSight's landing area. The soil particles here stick together more like those in a vat of flour, Tilman Spohn, a space scientist at the German Aerospace Center in Cologne, Germany told Nature, preventing the mole from digging deeper. 

To get around this problem, the team of scientists are pinning the mole to the side of the pit with the lander’s arm to give the instrument the required friction to dig further. The mole is starting to bury itself into the ground again, slowly and carefully, say scientists.

“By Christmas time, maybe our present will be that we’re back to square one. Which at this point in time would be a very, very welcome situation,” Spohn told Nature.

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