What lurks beneath the surface of Mars?
We’re coming up on two years since the NASA’s InSight lander touched down on the surface of Mars. Since then, it’s been performing all manner of experiments on the red planet, scanning the atmosphere, surface, and whatnot. More recently, though, InSight has deployed seismic probes into Mars’ depths in order to get an idea of its core components. Turns out it’s not that different from Earth.
Utilizing a seismometer, the lander can detect the seismic vibrations that flow through the planet’s various layers. These vibrations, known as “marsquakes,” provide a sort of echo map of the planet’s composition. The same techniques are used by seismologists here on Earth, though without the kind of infrastructure we have here on Earth, the InSight’s probes have to get a little creative.
“The traditional way to investigate structures beneath Earth is to analyze earthquake signals using dense networks of seismic stations,” said study co-author Sizhuang Deng. “Mars is much less tectonically active, which means it will have far fewer marsquake events compared with Earth. Moreover, with only one seismic station on Mars, we cannot employ methods that rely on seismic networks.”
While the planet is quieter, though, it’s that lack of seismic activity that has keep it relatively pristine throughout the eons. Mars presumably hasn’t changed that much since it first formed in the darkness who-knows-how-long ago, so by scanning the planet’s make-up, scientists can get a nearly untainted view of a primitive planet and its components.
“In the absence of plate tectonics on Mars, its early history is mostly preserved compared with Earth,” Deng said. “The depth estimates of Martian seismic boundaries can provide indications to better understand its past as well as the formation and evolution of terrestrial planets in general.”
Based on the lander’s current scans, there appears to be a relatively small divide between the crust and mantel of Mars. After that, there’s a large section where wadsleyite is built from olivine. Finally, 994 miles from the surface, lies Mars’ solid core. It’s very similar to the Earth’s make-up, though with some notable elemental differences. Now if we could just find a buried Martian city…