NASA’s InSight lander has picked up on some symphony of sounds on Mars. The spacecraft’s sensitive seismometer called the Seismic Experiment for Interior Structure (SEIS) is designed to listen for marsquakes that help scientists to determine how the seismic waves of these quakes move through the planet’s interior, revealing the deep inner structure of Mars for the first time.
In April 2019, the lander has measured and recorded the first marsquake. This was 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.
More than 100 events have been detected, and around 21 of them are strongly considered to be quakes.
Recently, NASA shared sounds from two quakes detected by SEIS. These occurred on May 22, 2019 (the 173rd Martian day, or sol, of the mission) and July 25, 2019 (Sol 235). The Sol 173 quake is about a magnitude of 3.7; the Sol 235 quake is about a magnitude 3.3.
Far below the human range of hearing, these sonifications from SEIS had to be speeded up and slightly processed to be audible through headphones.
On Earth, cracks in the crust seal over the long run after water fills them with new minerals. This enables sound waves to continue uninterrupted as they pass through old fractures. On the other hand, the Moon’s crust stays fractured and sound waves scatter for several minutes. Scientists suggest that the Martian crust is like a mix of the Earth’s crust and the Moon’s. Mars, with its cratered surface, is slightly more Moon-like, with seismic waves ringing for a minute or so, whereas quakes on Earth can come and go in seconds.
Constantinos Charalambous, an InSight science team member at Imperial College London who works with the SP sensors, said, “It’s been exciting, especially in the beginning, hearing the first vibrations from the lander. You’re imagining what’s happening on Mars as InSight sits on the open landscape.”