The Mars earthquake lifted the veil from within to an unprecedented degree, revealing astonishing details about the red planet’s crust, mantle, and core.
measurements by NASA’s InSight lander (internal exploration using seismic, geodesy and heat transfer studies) found some details, including a crust layer very different than previously understood, a mantle that is less dense than the surface and a larger and finer core. . The new results show that the density is lower than previously estimated. Scientists say these discoveries will affect not only our current understanding of the red planet, but also our understanding of the formation and evolution of this and other rocky worlds in the solar system.
Earth seismology is a relatively young science. The first measurement of the mantle was made in 1889, when German scientists recorded an earthquake that originated in Japan. Apollo astronauts placed four sites on the moon that could only capture large seismic waves. The Viking lander in the 1970s tried to measure Martian earthquakes, but interference from the wind meant that a clear signal was not reestablished.
Mars InSight Pictured: NASA’s mission to explore the core of the Red Planet
. Therefore, although scientists have learned about the interior of the Earth and the Moon, other rocky worlds remain a mystery. Instead, scientists rely on Martian meteorites, surface exploration, and observations of the orbiter’s magnetic field and gravity to initially characterize the interior of Mars.
Brigitte KnapmeyerEndrun, a researcher at the University of Cologne, Germany, told Space.com via email: “It’s like having a locked box and trying to determine what’s inside by getting general information from the outside.” KnapmeyerEndrun is today (July 22, Japan) is the first author of one of three insight studies published in the journal Science.
In contrast, InSight’s seismic survey is comparable to an X-ray box for a more comprehensive view.
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Thick or thin crust
For decades, landers and orbiters have been exploring the crust of Mars and examining materials on the surface to determine if the planet is made of is the thickness or thickness of its outer shell. Theorists used these measurements and the analysis of Martian meteorites to create models of the planet’s thin and thick layers. Some models estimate that the
crust is 68 miles (110 kilometers) thick, which is significantly thicker than the crust, which is between 3 and 44 miles (5 to 70 kilometers) thick.
Now, InSight has used seismic waves to measure the crust directly below its landing site, determined that there are at least two, but possibly three, hidden beneath the surface, and calculated the average cortical thickness of the entire planet.
When an earthquake or earthquake occurs, seismic waves will reverberate on the earth. The main wave or P splits and traverses the layers quickly. P waves are compression waves similar to sound waves propagating in the air. Following this is the secondary wave or S, the shear wave, whose vibration is perpendicular to the direction of the wave, just like a guitar string. The
measuring the amount of time between P and S waves allows researchers to determine the distance of an earthquake, because the arrival time is further from the origin. Waves also travel through different materials at different speeds, further changing the arrival time. Finally, waves can also be captured and reflected layer by layer, providing additional information about the interior of the planet.
“It’s true that under InSight, there are at least two layers in our crust,” said Knappmeyer Edlen. The top layer is about 10 kilometers (6 miles) thick. InSight observations show that the speed of waves traveling through the crust alone is much slower than expected based on observations of the surface.
Since the formation of the Earth’s crust, the “upper stratum is likely to be broken by multiple meteor impacts, and chemical changes can also occur,” KnapmeyerEndrun said.
The second layer extends to a depth of approximately 12 miles (20 kilometers) and may be more primitive than the first layer and is not affected by impacts or surface changes.
The next level down is more uncertain. KnapmeyerEndrun said there may be a third layer of the crust that extends to a depth of about 24 miles (39 kilometers) and is made up of a different material than the first two layers. Or at this time, the interior can pass to the mantle.
“More research is needed to really determine what the layers are,” he said.
Using InSight’s Mars seismic data and measurements of the gravity of all planets, the researchers determined that the average thickness of the Martian crust is between 14 and 45 miles (24 and 72 kilometers). The
new results are generally compatible with the thick and thin crust models of Mars. But KnapmeyerEndrun said what’s most surprising is the crust support that may be only 12 miles (20 kilometers) thick beneath the lander. He said that such a thickness “will be thinner than previously predicted, and it is difficult to reconcile with some early models.” However, this number is not certain, because a crust that is more than 24 miles (39 kilometers) thick can also explain the results. InSight will continue to study earthquakes until its extended mission ends in 2022, which may double the number of earthquakes observed.
“With more earthquakes and different types of analysis, we still hope to distinguish between the two cases during the extended mission,” KnapmeyerEndrun said.
Related: What is Mars made of?
The two largest earthquakes detected by NASA’s InSight lander seem to have originated in an area called Cerberus Forth, where signs of tectonic activity such as landslides have previously been detected. This photo was taken by NASA’s Mars Reconnaissance Orbiter.
The two largest earthquakes detected by NASA’s InSight lander seem to have originated in an area called Cerberus Forth, where signs of tectonic activity such as landslides have previously been detected. This photo was taken by NASA’s Mars.

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