Marsquakes Give Scientists Key Data on Interior of Red Planet

(CN) — An international team of researchers has used seismic activity on Mars to map the interior of the planet in greater detail than ever before.

In a trio of research papers appearing in the July 23 issue of the journal Science and published by the American Association for the Advancement of Science, scientists have begun to accurately map out the crust, mantle and core of Mars in hopes of better understanding the evolution and formation of the planet.

“These three studies provide important constraints on the present-day structure of Mars and are also key for improving our understanding of how the planet formed billions of years ago and evolved through time,” researchers Sanne Cottaar and Paula Koelemeijer wrote in a perspective on the studies.

The analyzed data comes from NASA’s Martian lander called InSight, which detected and recorded seismic activity from its position on the surface of Mars.

Using this information, scientists found evidence of a multi-layered crust, and were able to determine its thickness in absolute numbers for the first time.

The research team was headed by geophysicist Brigitte Knapmeyer-Endrun with the University of Cologne's Institute of Geology and Mineralogy and Mark Panning at NASA and California Institute of Technology's Jet Propulsion Laboratory,

“What seismology can measure are mainly velocity contrasts. These are differences in the propagation velocity of seismic waves in different materials,” Knapmeyer-Endrun said in a statement. "Very similar to optics, we can observe phenomena like reflection and refraction. Regarding the crust, we also benefit from the fact that crust and mantle are made of different rocks, with a strong velocity jump between them.”

The result of this analysis determined that the crust of Mars is between 20 or 39 kilometers (12 to 24 miles) thick and consists of multi-layers that are not made out of the same material.

“Rather, the data suggest that the uppermost layer is composed of an unexpectedly porous rock. Also, there could be other rock types at greater depths than the basalts seen at the surface,” Knapmeyer-Endrun said.

Using the single measurement from InSight and measurements from satellites orbiting Mars, the scientists could eventually provide an accurate map of the entire planet.

This new information about Mars' crust helps researchers figure out how the red planet evolved and helps illuminate how early differences in the development of Mars resulted in it being so vastly different than Earth.

The findings of the two other research papers dive below the crust of Mars and detail the mantle and core of the planet.

Amir Khan and fellow researchers used direct and surface reflected seismic waves from eight smaller marsquakes to look below the crust and reveal the next layer, called the mantle, to a depth of almost 800 kilometers (497 miles). In addition, it is believed that Mars’ crust layer is highly enriched in heat-producing radioactive elements.

The final paper of the trio used faint seismic signals to investigate the red planet’s core. Scientist Simon Stähler and his colleagues found that the red plant’s rather large liquid metal core has a radius of about 1,830 kilometers (1,137 miles) which begins about halfway between the surface and center of the planet.

These findings also suggest that the planet’s rocky mantle consists of only one rocky layer, unlike the two found in Earth. According to Stähler’s paper, the iron-nickel core of Mars is less dense then originally believed and is enriched in lighter elements.

“Direct seismic observations on Mars represent a major leap forward in planetary seismology,” Cottaar and Koelemeijer wrote in their perspective piece. “Over the coming years, as more marsquakes are measured, scientists will refine these models of the red planet and reveal more of Mars’ enigmatic mysteries.”

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