Sensors delivered to Mars by NASA's InSight lander had detected the first seismic signal on Mars, suggesting seismic activity on the Red Planet. This was a major discovery that extend the field of seismology to a new understanding beyond Earth.
Scientists announced the detection on Tuesday, characterizing the seismic signal as the first "likely" indication of a "Marsquake"
InSight's Seismic Experiment for Inetrior Structure (SEIS), instrument detected the signal on April 6. Scientists said the shaking could appear to have originated from the interior of the Red Planet, rather than from the wind or mechanical disturbances from the lander itself.
According to InSight scientists, rather than the movement of tectonic plates which generate quakes on Earth, they believe that the Martian tremors are generation by the cooling and contraction of the planet. Over time, the contraction build up stress until it is strong enough to break out of the crust and causing a quake.
Researchers are still studying the seismic data to determine the cause of the signal. NASA's Jet Propulsion Laboratory, where the InSight mission is managed, released an audio and video recording of the April 6 event illustrating the vibrations detected by the SEIS instrument.
NASA had also released the video and audio recorded by InSight on social media. You can clearly hear three distinct sounds coming from InSight. First would be the noise of the Martian wind. Secondly is the vibrations on the Red Planet itself and third is InSight's robotic arm moving to take pictures of the planet.