A recent meteor impact on Mars has unveiled the long-awaited information regarding the inner parts of the planet: it’s been found to contain a deep seismic highway, where seismic waves travel farther than is expected, making long-held models about Mars’ subsurface come into question and may lead to more accurate explanations about the development of rocky planets like Earth.
The discovery was based on comparing marsquake data from NASA’s InSight lander to the impact craters identified by the Mars Reconnaissance Orbiter (MRO). While scientists felt that the crust would dampen the seismic waves, researchers realized that in certain meteoroid impacts, the seismic waves travel deep into the planet’s mantle, which creates a more direct and energy-efficient pathway.
Published February 3 in Geophysical Research Letters, the new research indicates even a retired mission such as InSight will pay off into at least 2022: NASA’s first ever to position a seismometer on the red planet had reported over 1,300 marsquakes originating from within and impacting due to meteoroid hitting Mars.
One of the most surprising discoveries came from a newly formed impact crater in the Cerberus Fossae region, located about 1,019 miles (1,640 km) from InSight. The crater, measuring 71 feet (21.5 meters) in diameter, was much farther from the lander than expected based on the seismic energy recorded. Scientists believed previously that Mars’ crust absorbed the majority of the energy from impacts. The new data suggests, however, that some waves bypass the crust directly to the deeper parts of the mantle, traveling faster and deeper.
“We used to think most seismic energy was trapped in the crust, but this finding reveals a deeper, faster route—a seismic highway—through the mantle,” said Constantinos Charalambous of Imperial College London, a member of the InSight team.
This was achieved through a machine learning algorithm developed at NASA’s Jet Propulsion Laboratory. The AI tool quickly scans thousands of black-and-white images from the MRO’s Context Camera for fresh impact craters. The promising candidates are then examined in greater detail with the MRO’s High-Resolution Imaging Science Experiment (HiRISE) camera.
The scientists will then need to redevelop their models of Mars’ interior, redrawing the planet’s composition and structure. It might also affect future missions because it can give researchers better ways to predict seismic activity on Mars and other rocky planets.
