The two largest quakes detected by NASA’s InSight appear to have originated in a region of Mars called Cerberus Fossae. Scientists previously 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
Based on the analysis of marsquakes recorded by NASA’s InSight mission, the structure of Mars’ crust has now been determined in absolute numbers for the first time. Beneath the InSight landing site, the crust is either approximately 20 or 39 kilometers (12 or 24 miles) thick. That is the result of an international research team led by geophysicist Dr. Brigitte Knapmeyer-Endrun at the University of Cologne’s Institute of Geology and Mineralogy and Dr. Mark Panning at Jet Propulsion Laboratory, California Institute of Technology (Caltech). InSight stands for “Interior Exploration using Seismic Investigations, Geodesy and Heat Transport.” NASA’s lander, which landed on Mars on 26 November 2018, explores the crust, mantle and core of the red planet. The paper “Thickness and structure of the Martian crust from InSight seismic data” was published in the journal Science on July 23, 2021.
In the past, only relative differences in the thickness of Mars’s could be estimated, and additional assumptions were required to obtain absolute thicknesses. The resulting absolute values thus showed large scatter, depending on which assumptions were made. Seismology now replaces these assumptions with a direct measurement at the landing site, and thus calibrates the crustal thickness for the entire planet. This independent data point also allows estimating the density of the crust.
This is NASA InSight’s second full selfie on Mars. Since taking its first selfie, the lander has removed its heat probe and seismometer from its deck, placing them on the Martian surface; a thin coating of dust now covers the spacecraft as well. This selfie is a mosaic made up of 14 images taken on March 15 and April 11 – the 106th and 133rd Martian days, or sols, of the mission – by InSight’s Instrument Deployment Camera, located on its robotic arm. Credit: NASA/JPL-Caltech
“What seismology can measure are mainly velocity contrasts. These are differences in the propagation velocity of seismic waves in different materials,” said Knapmeyer-Endrun, lead author of the paper. “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.” Based on these jumps, the crust’s structure can be determined very precisely.
The data show that at the InSight landing site, the top layer is about 8 (+/-2) kilometers (5 miles) thick. Below that, another layer follows to about 20 (+/-5) kilometers (12 miles). “It is possible that the mantle starts under this layer, which would indicate a surprisingly thin crust, even compared to the continental crust on Earth. Beneath Cologne, for example, the Earth’s crust is about 30 kilometers (19 miles) thick,” Knapmeyer-Endrun explained. Possibly, however, there is a third crustal layer on Mars, which would make the Martian crust under the landing site about 39 (+/-8) kilometers (24 miles) thick. That would be more consistent with previous findings, but the signal from this layer is not essential to match existing data. “In both cases, however, we can rule out the possibility that the entire crust is made of the same material known from surface measurements and from Martian meteorites,” the geophysicist said. “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.”
This artist’s rendering shows a cutaway of the Seismic Experiment for Interior Structure instrument, or SEIS, which will fly as part of NASA’s Mars InSight lander. SEIS is a highly sensitive seismometer that will be used to detect marsquakes from the Red Planet’s surface for the first time. There are two layers in this cutaway. The outer layer is the Wind and Thermal Shield – a covering that protects the seismometer from the Martian environment. The wind on Mars, as well as extreme temperature changes, could affect the highly sensitive instrument. The inside layer is SEIS itself, a brass-colored dome that houses the instrument’s three pendulums. These insides are inside a titanium vacuum chamber to further isolate them from temperature changes on the Martian surface. Credit: NASA/JPL-Caltech/CNES/IPGP
The single, independent measurement of crustal thickness at the InSight landing site is sufficient to map the crust across the entire planet. Measurements from satellites orbiting Mars provide a very clear picture of the planet’s gravity field, allowing the scientists to compare relative differences in crustal thickness to the measurements taken at the landing site. The combination of these data provides an accurate map.
The crustal thickness of Mars is particularly interesting because the crust formed at an early formation stage from the remnants of a molten mantle. Thus, data on its present-day structure can also provide information on how Mars evolved. In addition, a more precise understanding of the evolution of Mars helps to decipher how early differentiation processes unfolded in the solar system and why Mars, Earth, and other planets are so different today.
Read NASA’s InSight Mission Reveals the Detailed Internal Structure of Mars for more on this research.
“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, 23 July 2021, Science.
DOI: 10.1126/science.abf8966
Jet Propulsion Laboratory (JPL) manages InSight for NASA’s Science Mission Directorate. InSight is part of NASA’s Discovery Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space in Denver built the InSight spacecraft, including its cruise stage and lander, and supports spacecraft operations for the mission.
A number of European partners, including France’s Centre National d’Etudes Spatiales (CNES) and the German Aerospace Center (DLR), are supporting the InSight mission. CNES provided the Seismic Experiment for Interior Structure (SEIS) instrument to NASA, with the principal investigator at IPGP (Institut de Physique du Globe de Paris). Significant contributions for SEIS came from IPGP; the Max Planck Institute for Solar System Research (MPS) in Germany; the Swiss Federal Institute of Technology (ETH Zurich) in Switzerland; Imperial College London and Oxford University in the United Kingdom; and JPL. DLR provided the Heat Flow and Physical Properties Package (HP3) instrument, with significant contributions from the Space Research Center (CBK) of the Polish Academy of Sciences and Astronika in Poland. Spain’s Centro de Astrobiologia (CAB) supplied the temperature and wind sensors.
The core of planet Mars is hard solid iron alloy core.Above the core lower mantle in fluid state is present,iron is the main constituent.Nonmetallic ingradiants fails to keep any presence,although some other metals are present.Rest part of the mantle is also dominated by iron,where some other metals and nonmetallic impurities at the top are constituents.Crust is present above the mantle in soĺìd form hàs average thickness of 39 Kms.Altough different as formed,crust òf the earth and crust of the mars,are rational or simillar in cooling process and time taken for it.This suggests simillarity regardig the age of these two planets.
The core of planet Mars is hard solid iron alloy core.Above the core lower mantle in fluid state is present,iron is the main constituent.Nonmetallic ingradiants fails to keep any presence,although some other metals are present.Rest part of the mantle is also dominated by iron,where some other metals and nonmetallic impurities at the top are constituents.Crust is present above the mantle in soĺìd form hàs average thickness of 39 Kms.Altough different as formed,crust òf the earth and crust of the mars,are rational or simillar in cooling process and time taken for it.This suggests simillarity regardig the age of these two planets.The mass,density and diameter for these two planets are different.Their average distance from the sun is different and inclination of orbits have different angles along with their own axes of rotation have different angle of inclination.But simillarity in age and cooĺing phenomena gives rational crust make them conjugate of each other,while these are consicutive as regardig to their distance from the sun.
The core of planet Mars is hard solid iron alloy core.Above the core lower mantle in fluid state is present,iron is the main constituent.Nonmetallic ingradiants fails to keep any presence,although some other metals are present.Rest part of the mantle is also dominated by iron,where some other metals and nonmetallic impurities at the top are constituents.Crust is present above the mantle in soĺìd form hàs average thickness of 39 Kms.Altough different as formed,crust òf the earth and crust of the mars,are rational or simillar in cooling process and time taken for it.This suggests simillarity regardig the age of these two planets.The mass,density and diameter for these two planets are different.Their average distance from the sun is different and inclination of orbits have different angles along with their own axes of rotation have different angle of inclination.But simillarity in age and cooĺing phenomena gives rational crust make them conjugate of each other,while these are consicutive as regardig to their distance from the sun.This can be a fine decision of nature’s law presented in solar system and corelates to the total laws of physics in the galaxies.
By comparing the mars with the earth,we can study them.
Their time period for one complete rotation around own axis and angle their orbits make at sun are nearly equal.
Now though they are different in size and mass are conjugately simillar to each other.To explain this fact,this can be cited that,their crusts thickness have nearly equal ratio with diameters.The ratios of their core radius to mantle thickness are approximately equal configurated with some compositional ratio and order.This ratio for Mars can be expressed as 1:4(_1).
Ĺikely,the same ratio for Earth is 1:8(+1).Here in both cases considering approximate values.
In planetary science of solar system,this fact can also be noted that these two planets are consecutive as their distance from the sun is regarded.
By comparing the mars with the earth,we can study them.
Their time period for one complete rotation around own axis and angle their orbits make at sun are nearly equal.
Now though they are different in size and mass are conjugately simillar to each other.To explain this fact,this can be cited that,their crusts thickness have nearly equal ratio with diameters.The ratios of their core radius to mantle thickness are approximately equal configurated with some compositional ratio and order.This ratio for Mars can be expressed as 1:4(_1).
Ĺikely,the same ratio for Earth is 1:8(+1).Here in both cases considering approximate values.
In planetary science of solar system,this fact can also be noted that these two planets are consecutive as their distance from the sun is regarded.
The endurance of earth’s core is so as to obtain tectonic plates in crust.While mars does not has any tectonic plate.