NASA’s InSight lander touched down on Mars in November 2018 carrying the most sensitive seismometer ever designed. Since the mission’s arrival at the Red Planet, it has detected countless seismic events, dubbed marsquakes, using the signals to map the planet’s interior. But the two newly announced quakes, classified as S0976a and S1000a, were something special. “Not only are they the largest and most distant events by a considerable margin, S1000a has a spectrum and duration unlike any other event previously observed,” said Anna Horleston, a seismologist at the University of Bristol. “They truly are remarkable events in the Martian seismic catalogue.”
The first seismic event, S0976a, was of magnitude 4.2 and occurred on 25 August 2021, originating in Valles Marineris, a vast network of canyons that extends for 4,000 kilometres (2,500…
