The northern hemisphere of Mars (shown in false color) is mostly lowlands (blue), while the southern hemisphere is higher and more mountainous. This elevation map of the Red Planet was created from data from NASA’s Mars Global Surveyor. MARS ORBITER LASER ALTIMETER SCIENCE TEAM

Planetary scientists now know how thick the Martian crust is, thanks to the strongest Marsquake ever observed.

On average, the crust is between 42 and 56 kilometers thick, researchers report in a paper to appear in Geophysical Research Letters. That’s roughly 70 percent thicker than the average continental crust on Earth.

The measurement was based on data from NASA’s InSight lander, a stationary seismometer that recorded waves rippling through Mars’ interior for four Earth years. Last May, the entire planet shook with a magnitude 4.7 quake that lasted more than six hours (SN: 5/13/22). “We were really fortunate that we got this quake,” says seismologist Doyeon Kim of ETH Zurich.

Scientists have simulated the path of seismic waves rippling across the red planet. The ways in which quakes look and feel differ depending on the materials they’re traversing, meaning they may act very differently than what we’re used to here on Earth, the space agency explains

Scientists have simulated the path of seismic waves rippling across the red planet.

NASA’s InSight lander detected its first marsquake earlier this year, providing on-the-ground data for the first time on the behaviors of these natural phenomena on Mars.

The ways in which quakes look and feel differ depending on the materials they’re traversing, meaning they may act very differently than what we’re used to here on Earth, the space agency explains.

A new animation shows just how this might play out beneath the surface of Mars.

NASA’s Mars InSight lander has measured and recorded for the first time ever a likely “marsquake.”

The faint seismic signal, detected by the lander’s Seismic Experiment for Interior Structure (SEIS) instrument, was recorded on April 6, the lander’s 128th Martian day, or sol. This is the first recorded trembling that appears to have come from inside the planet, as opposed to being caused by forces above the surface, such as wind. Scientists still are examining the data to determine the exact cause of the signal.

“InSight’s first readings carry on the science that began with NASA’s Apollo missions,” said InSight Principal Investigator Bruce Banerdt of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “We’ve been collecting background noise up until now, but this first event officially kicks off a new field: Martian seismology!”

The new seismic event was too small to provide solid data on the Martian interior, which is one of InSight’s main objectives. The Martian surface is extremely quiet, allowing SEIS, InSight’s specially designed seismometer, to pick up faint rumbles. In contrast, Earth’s surface is quivering constantly from seismic noise created by oceans and weather. An event of this size in Southern California would be lost among dozens of tiny crackles that occur every day.

“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,” said Lori Glaze, Planetary Science Division director at NASA Headquarters.

NASA’s InSight lander places a protective, dome-shaped shield above its seismometer. JPL-CALTECH/NASA

After months of delicate maneuvering, NASA’s InSight lander has finished placing its hypersensitive seismometer on the surface of Mars. The instrument is designed to solve mysteries about the planet’s interior by detecting the booming thunder of “marsquakes.” But just a few weeks into its run, the car-size lander has already heard something else: the minute tremors that continually rock our red neighbor. If marsquakes are the drum solo, these microseisms, as they’re known, are the bass line.

The signal first became apparent in early February, as soon as the lander placed a protective shield over the seismometer, said Philippe Lognonné, a planetary seismologist at Paris Diderot University who heads the team that runs the instrument, in a talk here today at the annual Lunar and Planetary Science Conference. “We do believe that these signals are waves coming from Mars.” This is the first time, he said, that such microseisms have been detected on another planet.

On Earth, microseisms are ubiquitous, caused largely by the sloshing of the ocean by storms and tides. Mars, despite the dreams of science fiction writers, has no present-day oceans. Instead, this newly discovered noise is likely caused by low-frequency pressure waves from atmospheric winds that rattle the surface, inducing shallow, longer-period waves in the surface, called Rayleigh waves, Lognonné said.