NASA’s Mars InSight lander has detected three of its most powerful earthquakes yet.
On August 25, InSight detected two earthquakes, with magnitudes 4.1 and 4.2. Then, on 18 September – the 1,000th Martian day of the lander’s operation – it picked up another 4.2 magnitude earthquake.
These new earthquakes blow the previous record of a magnitude 3.7 earthquake out of the water in 2019. Astonishingly, August’s largest earthquake was the farthest yet found, with its epicenter about 8,500 kilometers (5,280 mi) from InSight.
The analysis is still ongoing, but scientists are excited about the prospect of learning something new about the interior of the Red Planet.
“Even after more than two years, Mars has given us something new with these two earthquakes, which have unique features,” said Bruce Banerd, a planetary geophysicist at NASA’s Jet Propulsion Laboratory.
InSight, the primary instrument for detecting rumbles and rumbles on the surface of Mars, has been operational since 2018. During that time, the lander has given us a wealth of new information.
First, there was the direct detection of marsquakes in the first place. This is a big deal, because Mars was thought to be geologically dead. Now we know for sure that there is enough going on in the interior to make things tremble at times.
Second, marsquake data is allowing planetary scientists to map the Martian interior. When acoustic waves bounce off inside Mars and propagate through materials of different densities, the resulting signals can be decoded into what – and where – those materials are. This is how we map the interior of the Earth as well. As such, scientists determined earlier this year that Mars has a larger, lower-density liquid core than expected.
The newly discovered earthquakes bring something new to the table.
First, almost all major earthquakes detected by InSight so far are very close to its landing site, in an area called Cerberus Fosse, about 1,600 kilometers from InSight. Here, a series of cracks can be found, created by faults separating the crust. Evidence suggests that the region was tectonic and volcanically active recently, that is, within the last 10 million years.
Scientists have yet to analyze the September quakes, or pinpoint the exact epicenter of the two major August quakes, but they are looking at another area that shows signs of past volcanic activity – Valles Marineris, A massive canyon system that measures 4,000 kilometers across the face of Mars. The center of this system is 9,700 km from InSight.
The August 2 earthquakes also gave different seismic profiles. The 4.2 magnitude earthquake was slow and low frequency, and the 4.1 magnitude earthquake was stronger and more frequent. It was also very close at a distance of just 925 km from the lander.
Different seismic profiles can mean different processes are at play within Mars, but they also help in mapping the Mars interior above, as they can help put together more detailed reconstructions of the interior density. .
Insight, poor little one, really isn’t having an easy time of it. At first, there were some problems with its burrowing instrument, the MOL, which was designed to monitor heat flow. Mole was pronounced dead earlier this year. And, although the lander received a two-year mission extension, it encountered some electrical problems when its solar panels were covered in dust.
In May of this year, scientists cleverly corrected this by instructing InSight to seep sand next to the solar panels on a windy day. The larger grains hit and bounce off the panels, collecting smaller dust in the process, resulting in a significant strength boost. Several actions were taken, restoring the functionality of the lander.
“If we hadn’t acted early this year, we would have missed out on some great science,” Bannert said.