Mars has a liquid iron alloy core at its center. Using seismic data gathered by NASA’s InSight lander, planetary scientists have made the first observations of seismic waves traveling through Mars’ liquid iron core.
“In 1906, scientists first discovered the Earth’s core by observing how seismic waves from earthquakes were affected by traveling through it,” said Dr. Vedran Lekic, a researcher at the University of Maryland.
“More than a hundred years later, we’re applying our knowledge of seismic waves to Mars.”
“With InSight, we’re finally discovering what’s at the center of Mars and what makes Mars so similar yet distinct from Earth.”
On August 25 and September 18, 2021, NASA’s InSight lander detected two marsquakes on the opposite side of the planet — the so-called farside marsquakes.
The distance proved crucial: the farther a quake happens from InSight, the deeper into the planet its seismic waves can travel before being detected.
“We needed both luck and skill to find, and then use, these quakes,” said Dr. Jessica Irving, a researcher at the University of Bristol.
“Farside quakes are intrinsically harder to detect because a great deal of energy is lost or diverted away as seismic waves travel through the planet.”
“The two quakes occurred after the mission had been operating on the Red Planet for well over a full Martian year (about two Earth years), meaning the Marsquake Service — the scientists who initially scrutinize seismographs — had already honed their skills.”
“It also helped that a meteoroid impact caused one of the two quakes; impacts provide a precise location and more accurate data for a seismologist to work with.”
“Because Mars has no tectonic plates, most marsquakes are caused by faults, or rock fractures, that form in the planet’s crust due to heat and stress.”
“The quakes’ size was also a factor in the detections,” she added.
“These two farside quakes were among the larger ones…
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