Listening for Impacts on Mars

In January 2019, NASA's InSight mission placed the first seismometer on the surface of Mars to record tiny ground movements—marsquakes—produced by faulting, meteorite impacts and other geological processes. During nearly four years of successful operation, more than a thousand marsquakes have been used to determine how tectonically active the surface of Mars is today and to reveal the internal structure of Mars. Marsquakes definitively generated by meteorite impacts, however, were conspicuously absent during the first almost one thousand Mars days of operation. In late 2021, however, InSight detected several seismic signals with an unusual fingerprint, suggestive of a exogenic source. Subsequent imaging by orbiting spacecraft revealed the smoking gun: an impact crater or cluster of craters several metres across in each case.

The first confirmed seismic detections of meteorite impacts on Mars help us to understand the seismic hazard of impacts and allows a re-evaluation of the origin of dozens…