Disaster chain effects on landscape evolution following earthquakes in mountainous areas

Landslides and debris flows frequently occur in mountainous areas following earthquakes and, in turn, affect the evolution of the terrain. Following an earthquake, geological disasters no longer occur individually or sporadically and are instead typically clustered and chain-like. However, little attention has been given to the long-term effects of these disaster chains on landscape evolution processes following earthquakes. In this study, an earthquake-stricken area was selected as an example to study the disaster chain effects on landscape evolution. We predicted landslide occurrences in the long-term landscape evolution process and analyzed mass movements in response to future rainfall scenarios under disaster chain effects. The results showed that disaster chain effects are expected to directly affect the spatial material redistribution pattern under extreme rainfall conditions with increased sediment yields compared to the results derived without landslide effects under the same rainfall scenario; the difference in the cumulative sediment yield showed a positive linear correlation with time (\({R}^{2}\) = 0.8688) over the 50-year landscape evolution process. Regarding the landslide risk, the landslide-susceptible area tended to move upwards to the relatively high-elevation area, and the rainfall intensity expected to lead to great risks in the study area was the 20-year-return-period extreme rainfall amount; this finding was expected to remain unchanged over a long period of time. Thus, disaster chain effects greatly alter the locations at which landslides are most likely to occur. The results obtained in this research can provide scientific information for hazard management and mitigation.