Since early 2019, researchers from ETH Zurich have been recording and analysing marsquakes as part of the InSight mission. Using this data, they have now measured the red planet’s crust, mantle and core. The data will help understand the formation and evolution of Mars and, by extension, the entire solar system.
The researchers have discovered that the Martian crust under the probe’s landing site near the Martian equator is between 15 and 47 kilometres thick. Such a thin crust must contain a relatively high proportion of radioactive elements, which calls into question previous models of the chemical composition of the entire crust.
The mantle is 400–600 kilometres down, twice as thick as that of Earth. This could be because there is now only one continental plate on Mars, in contrast to Earth with its seven large mobile plates.
The measurements also show that the Martian mantle has a mineralogy similar to Earth’s upper mantle. The seismology reveals differences in chemical composition. The Martian mantle, for example, contains more iron than the Earth’s.
The Martian core has a radius of about 1,840 kilometres, making it a good 200 kilometres larger than had been assumed 15 years ago, when the InSight mission was planned.
The researchers were now able to recalculate the size of the core using seismic waves.
“Having determined the radius of the core, we can now calculate its density,” Simon Stähler of ETH Zurich says in a release.
