Hillslope memory of sequential earthquakes

Large earthquakes can trigger landslides that reshape mountain landscapes within minutes, yet their geomorphic legacy can unfold over millennia. A fundamental question is whether a major earthquake leaves hillslopes in a less or more stable state for the next. Here we exploit two sequential earthquakes (2013 and 2022) at close to the same location near Lushan, China, to quantify how the first event preconditions hillslope failure during the second. The 2013 earthquake produced a dual effect: Regional susceptibility declined as unstable material was removed, yet localized coseismic damage weakened a different population of hillslopes that later failed in 2022. These opposing outcomes generate three damage-recovery pathways of hillslope response that define how mass is redistributed and mechanical strength reorganizes according to a prolonged “hillslope memory” with implications for the landscape evolution of mountain belts. Hillslope response to sequential earthquakes is fundamentally path dependent, demanding landslide hazard assessments that explicitly incorporate history.