Abstract

Disasters triggered by extreme precipitation events i.e., landslides, debris flows, and floods cause devastating damages to lives, infrastructure, and the economy. Under a warming climate, precipitation extremes and the occurrence of debris flows are further expected to intensify. Driven by extreme runoff, the triggering of debris flows can be simultaneous. Their concurrent occurrence multiplies complexity in decision-making during emergencies. Despite advancements in geotechnics and network science, a systematic framework to analyze the impact of debris flows on road networks is lacking. While network science-based approaches work on large-scale, geotechnics-based damage assessments are done solely on a site-to-site basis. Here we develop an integrated approach to analyze the impacts of simultaneous debris flows on road networks. The approach includes a novel infinite slope-based one-dimensional numerical model that simulates runoff-induced erosion and a network science-based mathematical model for road failures. This study covers multiple catastrophic events of debris flows that occurred in different geological and climate settings i.e., post-earthquake, post-volcanic, and post-wildfire environments. We perform spatio-temporal simulations of initiation and runout of debris flows and calculate the damage caused on individual road segments. We validate the model results using metadata. Our results show even remote local disturbances caused by successive debris flows upstream may lead to complete cascading disruption of the network downstream. Our unified strategy opens avenues to understand the resilience of critical infrastructure networks against catastrophic debris flows.