Exploring the Application of a Debris Flow Likelihood Regression Model in Mediterranean Post-Fire Environments, Using Field Observations-Based Validation

Abstract

Post-fire geomorphic processes and associated risks are an important threat in Mediterranean environments. Currently, post-fire mass movement prediction has limited applications across the Mediterranean despite the abundance of both forest fires and landslide/debris flow disasters. This work applies a debris flow generation likelihood model to evaluate the probability of mass movement phenomena in different catchments of a burnt area, after a catastrophic fire near Schinos (Attica, Greece) in 2021. Then, it uses field observations from the area, recording mass movement phenomena after high-intensity rainfall events, to validate the results. The findings show that the model is successful in determining the probability of debris flow generation in the 21 basins of the study area, ranging from 0.05 to 0.893. The probability values show a statistically significant correlation (sig. = 0.001) with the actual debris flow occurrences in the area, and satisfactory results in terms of the model’s predictive ability, functioning well within the particular geo-environmental characteristics of the Mediterranean environment. The results establish the reliability of the approach as a tool to assess mass movement risks in a region with an abundance of post-fire related hazards and disastrous events.

A Prefire Approach for Probabilistic Assessments of Postfire Debris‐Flow Inundation

“…Previous work has established methods for estimating debris‐flow likelihood (Staley et al., 2017) and volume (Gartner et al., 2014) at the watershed scale in the western USA based on terrain and soil characteristics, burn severity, and peak 15‐min rainfall intensity. Models for postfire debris‐flow likelihood and volume have also been developed and applied in other fire‐prone regions, including the Mediterranean and Australia (Diakakis et al., 2023; Nyman et al., 2015). However, while a number of models, such as RAMMS (Christen et al., 2010), FLO‐2D (O’Brien et al., 1993), D‐Claw (George & Iverson, 2014; Iverson & George, 2014), and ProDF (Gorr et al., 2022), simulate PFDF inundation with comparable results (Barnhart et al., 2021), debris‐flow inundation estimates are not currently standard practice in postfire hazard assessments (Barnhart, Miller, et al., 2023; Barnhart, Romero, & Clifford, 2023).…”