Runout-modelling of shallow landslides in Carinthia (Austria)

Abstract

Shallow translational landslides and earth-flows (mixing process between landslide and flow process) are the most common and most problematic types of landslides relating to the weathering of the bedrock and unconsolidated slope deposits in Carinthia. These types of landslides can reach high speeds and travel long distances. Usually only the uppermost meters of loose sediments of the slope are affected and heavy rain events after a pre-saturation of the soil are typically triggers for such landslides.As part of a research project in Carinthia an Add-In for ArcGIS 10x was developed. This Add-In calculates the runout for these common types of mass movements on the basis of available data on a regional scale. The runout modelling assumes that the soil is presaturated and additional precipitation in susceptible area triggers the landslides. The calculation of the runout distances is performed using a specially programmed ArcGIS Add-In. The calculation requires the following information:Initiation cells of high susceptibility to landslide processes (slope failure initiation zones); digital elevation model (DEM); geology; surface roughness (generated from the landuse map); and curvature (this affects the drainage of the mass movement).The runout modelling takes into account the variability of the "trigger" and mobility as a function of water saturation in shallow landslides. The calibration of the parameters is based on simulations of initiation cells with known events so that it can be assumed that the simulation results match the conditions corresponding to events observed in the region. The model allows easy and fast recalculation for parts of the area if needed (new findings due to events).

Threshold or Limit? Precipitation Dependency of Austrian Landslides, an Ongoing Challenge for Hazard Mapping under Climate Change

“…A higher average intensity is a sign of steady, rich rainfalls preceding a, not necessarily extreme, ultimate event. The important role of presaturation has been pointed out by various authors (e.g., [28,41,42]), notably also for one Austrian province included here [43]. However, the considerable additional monitoring effort excludes it from many studies; antecedent rainfall factors in in less than one tenth of the 2600 observations compiled in [26].…”

Modeling Shallow Landslide Runout Distance in Eocene Flysch Facies Using Empirical–Statistical Models (Western Black Sea Region of Türkiye)

“…For many years, researchers have studied landslides using existing runout methods, which are empirical-statistical methods, physical methods, and numerical models. The empirical-statistical model was applied in studies by Poltnig et al [3], Kaafarani et al [4], Mergili et al [5], Zhou et al [6], Apriani et al [7], Di Napoli et al [8],…”

“…Nevertheless, recent studies point out that although researchers have used various methods over the years to investigate methods of estimating runout distance that may contribute to landslide risk evaluations, empirical-statistical methods are still generally preferred because of computational costs [37]. The reach angle method was often considered as an empirical method by many researchers [3,4,38,39]. The multiple flow direction [40], Holmgren [41], modified Holmgren [42], cellular automata [43], and random walk [44,45] models provide opportunities to simulate possible runout paths.…”