A country-wide spatial assessment of landslide susceptibility in Romania

Abstract

This paper proposes a brief spatial analysis of landslides in Romania, completed by a landslide susceptibility model. Landslides constitute a very common geomorphic hazard in this country, mainly in the hilly regions which occupy around 30% of Romania's territory. The landslide susceptibility assessment at national level was accomplished using a Landslide Susceptibility Index (LSI) computed in GIS, which considers and weights the main factors that control landslide activity: lithology, slope gradient, maximum rainfall in 24 h, land use, seismicity and local relief. Each factor was classified into 7–18 classes which were rated from 1 to 10 by means of expert judgement. A formula was devised to compute the Landslide Susceptibility Index over each 100 m × 100 m pixel and the resulting values were ranked into 5 landslide susceptibility classes. This synthetic method of landslide susceptibility assessment, applied to the whole country, is a useful tool to evaluate the distribution of landslide-prone areas, as well as to validate and to enhance some results obtained in previous studies based on field research and map interpretation. The most landslide-prone areas correspond to the Subcarpathians (an outer fringe of hilly terrain accompanying the Carpathians), as well as to the Moldavian Plateau in the east. The semi-quantitative approach has been validated with satisfactory results in a particular sector using independent cartographic landslide inventories.