[ad_1]
Artist’s impression of the internal structure of Mars. Credit: © IPGP / David Ducros
The first direct seismic observations of NasaInSight’s InSight lander, featured in three studies in this issue, provides clues to the composition of March. Researchers in these studies report preliminary results from the Insight mission and begin to map – for the first time – the interior of a planet outside of Earth.
“These three studies provide important stresses on the current structure of Mars and are also essential for improving our understanding of how the planet formed billions of years ago and evolved over time,” write Sanne Cottaar and Paula Koelemeijer from a related perspective.
Studying a planet’s inner layers – its crust, mantle, and core – can reveal key information about its formation and evolution, as well as uncover any geomagnetic and tectonic activity it harbors. Such deep interior regions can be probed by measuring waves passing through the planet’s body as a result of seismic events such as an earthquake. Such methods have played a decisive role in the study of the internal characteristics of the Earth.
The two largest earthquakes detected by NASA’s InSight appear to originate from a region of Mars called Cerberus Fossae. Scientists have already spotted signs of tectonic activity here, including landslides. This image was taken by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter. Credit: NASA / JPL-Caltech / University of Arizona
In early 2019, NASA’s InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) Martian lander began detecting and recording earthquakes from its position on the surface of Mars, including several earthquakes below -crustals that resemble tectonic events on Earth. Brigitte Knapmeyer-Endrun and her colleagues used earthquakes and ambient seismic noise to image the structure of the Martian crust below the InSight landing site, finding evidence of a multi-layered crust with two or three interfaces. By extrapolating these data to the whole planet, Knapmeyer-Endrun et al. show how the average thickness of the crust of Mars is between 24 and 72 kilometers (km).
Amir Khan et al. used direct and reflected surface seismic waves from eight low-frequency earthquakes to probe deeper and reveal the structure of Mars’ mantle to a depth of nearly 800 km. Their findings suggest that a thick lithosphere lies nearly 500 km below the surface and, like Earth, likely has a low velocity layer below. According to Khan et al., The crustal layer of Mars is probably highly enriched in radioactive heat-producing elements, which heat this region to the detriment of the interior of the planet.
Illustration of NASA’s inner exploration using seismic, geodesy and heat transport (InSight) surveys Credits: NASA
More deeply still, Simon Stähler and his colleagues used the weak seismic signals reflected from the Martian core-mantle boundary to study the Martian core. They discovered that the relatively large liquid metal core of Mars has a radius of nearly 1,830 kilometers and begins roughly halfway between the surface and the center of the planet, suggesting that the planet’s mantle consists of of a single layer of rock, rather than two, as on Earth. . According to Stähler et al., The results indicate that the iron-nickel core is less dense than previously thought and enriched with lighter elements.
“Direct seismic observations on Mars represent a big step forward in planetary seismology,” write Cottaar and Koelemeijer. “In the years to come, as more and more earthquakes are measured, scientists will refine these models of the red planet and reveal more enigmatic mysteries of Mars.”
To learn more about this research:
The references:
“Structure of the upper mantle of Mars from InSight seismic data” by Amir Khan, Savas Ceylan, Martin van Driel, Domenico Giardini, Philippe Lognonné, Henri Samuel, Nicholas C. Schmerr, Simon C. Stähler, Andrea C. Duran, Quancheng Huang, Doyeon Kim, Adrien Broquet, Constantinos Charalambous, John F. Clinton, Paul M. Davis, Mélanie Drilleau, Foivos Karakostas, Vedran Lekic, Scott M. McLennan, Ross R. Maguire, Chloé Michaut, Mark P. Panning, William T . Pike, Baptiste Pinot, Matthieu Plasman, John-Robert Scholz, Rudolf Widmer-Schnidrig, Tilman Spohn, Suzanne E. Smrekar and William B. Banerdt, July 23, 2021, Science.
DOI: 10.1126 / science.abf2966
“Seismic detection of the Martian core” by Simon C. Stähler, Amir Khan, W. Bruce Banerdt, Philippe Lognonné, Domenico Giardini, Savas Ceylan, Mélanie Drilleau, A. Cecilia Duran, Raphaël F. Garcia, Quancheng Huang, Doyeon Kim, Vedran Lekic, Henri Samuel, Martin Schimmel, Nicholas Schmerr, David Sollberger, Éléonore Stutzmann, Zongbo Xu, Daniele Antonangeli, Constantinos Charalambous, Paul M. Davis, Jessica CE Irving, Taichi Kawamura, Martin Knapmeyer, Ross Maguire, Angela G. Marusiak, Mark P. Panning, Clément Perrin, Ana-Catalina Plesa, Attilio Rivoldini, Cédric Schmelzbach, Géraldine Zenhäusern, Éric Beucler, John Clinton, Nikolaj Dahmen, Martin van Driel, Tamara Gudkova, Anna Horleston, W. Thomas Pike, Matthieu Plasman and Suzanne E . Smrekar, July 23, 2021, Science.
DOI: 10.1126 / science.abi7730
“Thickness and structure of the Martian crust from InSight seismic data” by Brigitte Knapmeyer-Endrun, Mark P. Panning, Felix Bissig, Rakshit Joshi, Amir Khan, Doyeon Kim, Vedran Lekic, Benoit Tauzin, Saikiran Tharimena, Matthieu Plasman, Nicolas Compaire, Raphael F. Garcia, Ludovic Margerin, Martin Schimmel, Éléonore Stutzmann, Nicholas Schmerr, Ebru Bozdag, Ana-Catalina Plesa, Mark A. Wieczorek, Adrien Broquet, Daniele Antonangeli, Scott M. McLennan, Henri Samuel, Chloé Michaut, Lu Pan, Suzanne E. Smrekar, Catherine L. Johnson, Nienke Brinkman, Anna Mittelholz, Attilio Rivoldini, Paul M. Davis, Philippe Lognonné, Baptiste Pinot, John-Robert Scholz, Simon Stähler, Martin Knapmeyer, Martin van Driel, Domenico Giardini and W Bruce Banerdt, July 23, 2021, Science.
DOI: 10.1126 / science.abf8966
[ad_2]
Source link