NASA’s InSight lander has detected what scientists believe to be a marsquake for the first time since its mission began, NASA announced on Tuesday. The spacecraft has been on the surface of Mars since last year November as part of an ongoing mission to listen for quakes on the red planet. The probe’s seismometer (SEIS) has been on its active mode since December, but recorded the first quake only on April 6, on the 128th Martian day (or sol) of the mission. It was a such a small quake that it wouldn’t have been registered even on the Earth, but this is a major step for the lander’s overall mission.
While the cause of the slight quake could have been wind or other external forces, the InSight team is very confident that it came from the Mars itself. However, the quake was not big enough to provide data on the Martian interior which is one of InSight’s main goals. The seismometer measured three other signals of activity since the first one, but they have all been even weaker than the first.
The marsquake is comparable to the seismic activity measured on the moon during the Apollo missions that were carried out between 1969 and 1977. During that period, astronauts measured thousands of quakes.
Mars and the moon lack tectonic plates unlike the earth, so their quakes are caused by fractures or faults in their crusts. The Martian surface unlike the earth is much quieter than Earth, which is why the seismometer was able to pick up such faint rumbles.
In a recording released by the NASA, three distinct sounds can be heard: that of the wind, the supposed quake and the lander’s robotic arm working to take pictures. Since the actual vibrations would be undetectable to the human ear, the sound recording has been sped up by a factor of sixty.