Landslide inventory verification in the pilot area Hrvatsko zagorje

In the pilot area in the City of Lepoglava and the Municipality of Bednja, field research was done in order to verify the landslide inventory map. This map was created as a result of the previous phase of scientific research conducted within the Croatian Science Foundation LandSlidePlan project – collecting data for landslide susceptibility assessment.

The collection of landslide data for creating a landslide inventory map was carried out by remote sensing, based on cartographic data obtained by laser airborne scanning (LiDAR). Innovative aerial laser scanning technology has enabled to create a series of morphological maps for the pilot area in Hrvatsko zagorje. A special feature of this technology is the recording of morphological maps of the terrain below the vegetation, which is especially important for determining existing landslides, because landslides are usually overgrown with dense vegetation, covered with shrubs or trees.

Field research confirmed that an optimal DEM was developed by laser scanning and subsequent spatial analyzes, which enabled the visual identification of landslides in this pilot area.

More than seven hundred landslides of various sizes were contoured in a detailed scale (M1: 100–1: 500) in an area of 20 square kilometres using GIS. The contours of the landslides, i.e. the boundaries were checked in the field research. In addition to the landslide map, several morphometric maps were derived from LiDAR DEM, which enabled better orientation in the field as well as in landslide recognition. Field research of landslides was done on about 5% of randomly selected visually mapped landslides in the inventory, and it is planned to continue until a satisfactory representative number of verified landslides is achieved. A total of three collaborators on the Croatian Science Foundation LandSlidePlan project, scientists involved in landslide research, including a doctoral student on the Croatian Science Foundation Junior Researchers’ career development project DOK-2020-01-2432, participated in the field test.