A French device in the American Marslander InSight measured the quake on May 4. The InSight landed on Mars in 2018 and has recorded more than 1,300 quakes since then. Until last week, the strongest of these was a 4.2 magnitude quake in August last year.
The American space agency NASA cannot yet say exactly where the quake happened and what caused the vibrations. Further research should clarify this. Quakes can tell something about the composition of the interior of Mars.
