Recent landslides from Iași Metropolitan Area

Abstract

The creation and analysis of landslide inventories is the basic approach for starting the landslide hazard to risk analysis chain analysis. In order to perform this kind of analysis for the Iași Municipality (North–eastern Romania) we created based on aerial imagery and LiDAR data a landslide inventory of the landslide events that happened in the last 100 years. In total, we identified and delineated 518 landslide events: 51.5% translational slides, 19.7% slumps (rotational slides), 17% flowslides and 11.8% flows. The majority (74%) of the landslides events happened between 1956 and 1984, those before 1956 representing 16%, while those triggered after 1984 representing 10%. This situation reflects the very humid period between 1960 and 1990, when the majority of the landslide events were triggered. Beside the typology we have also identified the triggering factors and we can conclude that rainstorms coupled with previous rainy years were the main triggering factors, especially for Holocene old and relict landslides in areas with land use and anthropic disturbances created by the built up area expansion. The analysis of the landslide area frequency density is showing that the shape of the distribution curve is similar with what was reported in the literature, which is signaling that this inventory can be used further in landslide susceptibility modelling and validation. Further analysis of these events can also pinpoint scenarios for vulnerability and riskanalysis.