Two major meteorite impacts are revealing insights into the interior of the Red Planet

Representation of a Martian meteorite impact

Representation of the December 24, 2021 meteor impact (S1094b) on Mars and surface wave propagation to the InSight mission’s SEIS seismometer. Credit: © IPGP – CNES – N. Starter

By studying seismic and orbital data from two major meteor impacts in late 2021, teams[{” attribute=””>NASA’s InSight and

Meteor impacts play a role in shaping the surfaces of planets in our solar system, but it is not uncommon for there to be records of such high-energy impact signals. On Earth, our atmosphere acts as a shield, causing most meteorites to either burn up or explode at high altitudes before reaching Earth. Few other solar system bodies are equipped with seismometers to record impacts. While natural influences were recorded on the Moon, it was impossible to correlate the strongest of them with the image of the crater, which made it possible to determine its exact characteristics.

On Mars, impacts previously recorded by Insight’s SEIS instrument were 300 kilometers (200 miles) away and were associated with craters about 10 meters (33 feet) in diameter. This data, via analysis of sound waves, has really improved our knowledge of the local structure of the cortex.

Representation of the S1000a Mars meteor impact

Representation of the September 18, 2021 meteor impact (S1000a) observed by the Mars Reconnaissance Orbiter mission satellite and the propagation of various types of waves, within the mantle and up to the interface/core interface of Mars detected by the InSight mission’s SEIS seismometer. Credit: © IPGP – CNES – N. Starter

Impacts S1000a and S1094b, on September 18 and December 24, 2021, respectively, left two fingerprints over 130 meters (425 feet) in diameter on the Martian surface. S1094b is even the largest impact crater in the past few centuries discovered on Earth, with its 150-meter (500-foot) diameter exceeding the 120-meter (400-foot) Wabar crater in Saudi Arabia, and is considered the largest impact on Earth’s surface during this time. period, several decades before the first seismographs were published at the beginning of the 20th century. The same is true of Mars, where no impact of this magnitude has been detected by the Mars Reconnaissance Mission (MRO) since it began its orbital mission 16 years ago.

By combining seismic data from SEIS Insight cameras and MRO’s CTX, MARCI, and HiRISE cameras, the international teams of the two NASA missions were able to pinpoint the exact location of these two events in time and space: The accuracy of the Mars Reconnaissance Orbiter. This allows us to better understand how the energy of such a polyide is distributed during collisions in the Earth’s interior and in the atmosphere. In addition, we now have two seismic sources with an equivalent magnitude greater than 4, and their location is completely known on Mars, which allows us to verify Our models of the internal structure of the upper mantle and crust, which were especially developed in the framework of the MAGIS project, are correct,” says Philippe Lugnoni, scientific leader of the SEIS experiment at the Institute of Physics of the World in Paris, second author of one of the two articles, and coordinator of the MAGIS project funded by French National Research Agency (ANR), and Professor at the University of Paris City.

Artist's impression of a Martian meteorite

Artist’s impression of a meteor impact on December 24, 2021 in the Amazonis Planitia region of Mars. Credit: © IPGP -CNES – N. Starter

The two meteoroids hit Mars 3,500 kilometers (2,200 miles) and 7,500 kilometers (4,600 miles) from InSight’s landing site. The largest mass is estimated at 250-650 tons, for an impact velocity of 7.5 km/s. Both released enough energy to generate both surface and volume waves that propagated all the way to the Martian core.

For Eric Beauclair, professor at the University of Nantes and co-author of the articles, “These are the first events in which surface waves are clearly visible. This makes it possible to determine the average structure of the Martian crust between the point of impact and InSight.” These crustal thickness measurements are key to understanding the evolution of Mars, and were so far only possible under the InSight station thanks to earthquake-sized waves. Further observations of surface waves have been made since then, particularly after the detection of a magnitude 4.7 earthquake on May 4, 2022, which will allow these analyses to be completed.

A few weeks before the fourth anniversary of its landing on Mars, the InSight mission and its main instrument, the SEIS seismometer, made it possible to build the first models of the internal structure of Mars and to observe both the earthquakes of the planet and the very strong impacts that a planet with a weak atmosphere can experience.

Thierry Damerval, President and CEO of the French National Agency for Research (ANR), said: “With the MAGIS project and this unique data recorded by InSight and MRO, the work of the Franco-American teams at the IPGP and Los Alamos National Laboratory (LANL) will enable us to gain a better understanding of the powerful planetary forcings.” Too much for meteorites.”

“Mars continues to surprise us,” said Antoine Petit, CNRS President and CEO. Analysis of InSight and Mars Orbiter data by international teams, including a large number of scientists from our laboratories, helps refine our knowledge of the interior of Mars and demonstrates the importance of these missions. satellites for a better understanding of the solar system. This work prefigures the future FSS (Persian Seismic Wing) lunar mission, which aims to place an independent seismometer on the far side of the moon.”

And for Philippe Baptiste, Head of CNES, “These are remarkable results that show the suitability of the SEIS instrument and its very high level of performance. Mars continues to reveal its secrets. With one of the spare SEIS sensors, the FSS mission will take over in 2025 on the lunar surface. After that, the Propulsion Laboratory will be able JPL, CNES, IPGP and their partners are able to examine the interior of the Moon for the first time since the Apollo missions.”

For more information about this research:


“The Largest Recent Impact Craters on Mars: Orbital Imaging and Surface Seismic Investigation” by LV Posiolova, P. Lognonné, WB Banerdt, J. Clinton, GS Collins, T. Kawamura, S. Ceylan, IJ Daubar, B. Fernando, M. Froment , D. Giardini, MC Malin, K. Miljkovic, SC Stähler, Z. Xu, ME Banks, É. Beukler BA Cantor, Charalambos C, Dahmen N, Davis B, Drilo M, Dundas CM, Doran C, Yukner F, Garcia RM. Golombek, A. Hurleston, C. Keegan, A. Khan, D. Kim, C. Larmat, R. Lorenz, L. Margerin, S. Menina, M. Panning, C. Pardo, C. Perrin, WT Pike, M. Plasman, A. Rajšic, L. Rolland, E. Rogier, J. Speth, A. Spiga, A. Stott, D. Sciences.
DOI: 10.1126/science.abq7704

“Surface Waves and Crust Structure on Mars” by D. Kim, WB Bannerdt, Celan S, Giardini V, Lekic, Leknone P, Begin C, E. Beukler, S. Carrasco, C. Charalambos, J. Clinton, M. Drilo, C. Doran, M. Golombek, R. Joshi, A. Khan, B. Napmayer-Endron, J. Lee, R. Maguire, W.T. Pike, H. Samuel, M. Schimmel, N. C. Schmerr, S. C. Stähler, E. Stutzmann, M. Wieczorek, Z. Xu, A. Batov, E. Bozdag, N. Dahmen, P. Davis, T. Gudkova, A. Horleston, Q. Huang, T. Kawamura, SD King, SM McLennan, F. Nimmo, M. Plasman, A.C. Plesa, I.E. Stepanova, E. Weidner, G. Zenhäusern, IJ Daubar, B. Fernando, RF Garcia, LV Posiolova and MP Panning Oct. 27, 2022, Available Here. Sciences.
DOI: 10.1126/science.abq7157

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