Impact of communal irrigation on the 2018 Palu earthquake-triggered landslides

Anthropogenic changes to the environment can enhance earthquake-triggered landslides, yet their role in earthquake disasters is often overlooked. Co-seismic landslides frequently involve liquefaction of granular materials, a process that reduces shear strength and facilitates downslope motion even on gentle slopes. Irrigation systems can increase liquefaction susceptibility and compromise otherwise stable slopes. Here we investigate devastating landslides that affected Palu, Indonesia, during the 28 September 2018 earthquake of moment magnitude 7.5. We document fields and buildings translated over 1 km down slopes of