A data-driven evaluation of post-fire landslide susceptibility.

Wildfires change the hydrologic and geomorphic response of watersheds, which has been associated with cascading hazards that include shallow landslides and debris flows. This study evaluates post-wildfire landslide trigger characteristics by comparing precipitation preceding landslides at both burned and unburned locations. Landslide events are selected from the NASA Global Landslide Catalog (GLC) to facilitate regional inter-comparison. Fire and precipitation histories for each site are established using MODIS global burned area and CHIRPS precipitation data, respectively. Analysis of normalized seven-day accumulated precipitation for sites across all regions shows that, globally, landslides at burned sites are preceded by less precipitation than landslides without antecedent burn events. This supports the hypothesis that fire increases rainfall-driven landslide hazards. An analysis of the seasonality of landslides at burned and unburned locations shows that landslide-triggering storms in burned locations tend to exhibit different seasonality from other rainfall-triggered landslides, with a variety of seasonal shifts ranging from approximately six months in the Pacific Northwest of North America to one week in the Himalaya region. Overall, this manuscript offers an exploration of regional differences in the characteristics of rainfall-triggered landslides over a broad spatial scale and encompassing a variety of climates, geographies, and burn conditions. [ABSTRACT FROM AUTHOR]