A hybrid approach to earthquake-preconditioned debris flow: regional susceptibility and event-based hazard assessments

This study presents the first integrated debris flow susceptibility and numerical modelling framework applied under post-seismic conditions in Türkiye. The Tut region of Adıyaman in southeastern Türkiye experienced destructive debris flow events on 15 March 2023, following a period of intense rainfall under post-seismic conditions. These flows were spatially and temporally associated with the destabilizing effects of the Kahramanmaraş earthquake sequence, which had earlier weakened slope materials generating extensive coseismic landslide debris and initiating destructive debris flows in a region where these processes had not previously been documented.

The results demonstrate that machine learning-based susceptibility mapping provides an effective regional overview of debris flow source potential, while physically based numerical simulations are essential for quantifying flow dynamics and potential impacts. Their integration offers a more comprehensive understanding of debris flow hazards than either approach alone.