Successfully touching down on the Red Planet on November 26, 2018, the Mars InSight lander was sent there to study the interior of Mars.
It does this by using sophisticated geophysical instruments that will delve deep beneath the surface to detect the fingerprints of the processes of terrestrial planet formation. You can read more about the Mars InSight Lander in my article about the mission.
After spending the last five months on our rusty neighbor, the InSight lander has measured and recorded, for the first time ever, a likely “Marsquake.”
The seismometer on InSight was placed on the planet’s surface on December 19, 2018. It enables scientists to gather data about the internal workings of Mars. Over the course of the last four months, the sensitive instruments have detected four seismic signals in total.
Three of these occurred on March 14 (Sol 105), April 10 (Sol 132), and April 11 (Sol 133) and were detected by InSight’s more sensitive Very Broad Band sensors. Unfortunately, they were very small and ambiguous in origin, so thus cannot be ruled as quakes at this time. However, the team plans to continue studying the data collected about these events to determine their cause.
In between those events, was the interesting one recorded on April 6 (Sol 128). This is the first recorded trembling that appears to have come from inside the planet. You can listen to that recording here.
“The Martian Sol 128 event is exciting because its size and longer duration fit the profile of moonquakes detected on the lunar surface during the Apollo missions,” says Lori Glaze, Planetary Science Division Director at NASA Headquarters.
NASA astronauts that flew on the Apollo missions installed five seismometers that measured thousands of quakes on the moon between 1969 and 1977. Because different materials can change the speed of seismic waves, and even reflect them, measuring these can allow scientists to learn about the interior of a terrestrial body. Measuring these different types of seismic waves can give us insight (pun intended) into how the rocky planets formed.
Though this new seismic event was too small to provide solid data on the Martian interior, the Sol 128 signal is an exciting milestone for the team.
“We are delighted about this first achievement and are eager to make many similar measurements with SEIS in the years to come,” says Charles Yana, SEIS Mission Operations Manager at Centre National d’Études Spatiales (CNES).
Since Mars, like the Moon, does not have tectonic plates, quakes occur differently than they do on Earth. Contrary to quakes on Earth, which occur on faults created by the motion of the plates, Marsquakes are caused by a continual process of cooling and contraction that creates stress within the crust.
This stress builds over time until it is strong enough to break the crust, causing a quake. But until now, no one was sure if this process still occurred on the Red Planet.
“We’ve been waiting months for a signal like this,” says Phillippe Lognonné, SEIS Team Lead at the Institut de Physique du Globe de Paris (IPGP) in France. “It’s so exciting to finally have proof that Mars is still seismically active. We’re looking forward to sharing detailed results once we’ve had a chance to analyze them.”