NASA's robotic Mars InSight lander has recorded a likely "marsquake" for the first time ever, the US space agency said.
"We've been collecting background noise up until now, but this first event officially kicks off a new field: Martian seismology!"
NASA has been looking for such seismic activity for nearly five months months (or 128 Martian days) since InSight touched down on the planet, using the lander's Seismic Experiment for Interior Structure (SEIS) instrument. Scientists are still examining the data to conclusively determine the precise cause of the signal, but the trembling appeared to have originated from inside the planet, as opposed to being caused by forces above the surface, such as wind.
According to NASA, movement was detected on InSight's Seismic Experiment for Interior Structure (SEIS) instrument on the lander's 128th Martian day. Bruce Banerdt, a geologist at NASA's Jet Propulsion Laboratory in Pasadena, California, and the principal investigator of the InSight mission, said in a statement.
In contrast, Earth's surface is quivering constantly from seismic noise created by oceans and weather. What is known for sure is that Earth is no longer the only planet to be monitored by seismometers.
The scientists revealed that three other signals, which occurred on 14 March (Sol 105), 10 April (Sol 132) and 11 April (Sol 133), could also have been of seismic origin. If confirmed, it would be the first seismic activity ever detected on Mars. "We're looking forward to sharing detailed results once we've studied it more and modeled our data". While further tests are needed to prove it, they believe it was made by what would be roughly equal to a small, 2.5 magnitude quake back on Earth.
This stress builds over time, until it is strong enough to break the crust, causing a quake.