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Overview of Input Data for the Landslide Hazard Analysis in the Dubračina River Basin


Đomlija, Petra; Bernat, Sanja; Benac, Čedomir; Mihalić Arbanas, Snježana; Zidarić, Martin
Overview of Input Data for the Landslide Hazard Analysis in the Dubračina River Basin // Book of Abstracts / Vlastelica, Goran ; Andrić, Ivo ; Salvezani, Daša (ur.).
Split: University of Split, Faculty of Civil Engineering, Architecture and Geodesy, 2013. str. 63-64 (predavanje, nije recenziran, sažetak, znanstveni)


Naslov
Overview of Input Data for the Landslide Hazard Analysis in the Dubračina River Basin

Autori
Đomlija, Petra ; Bernat, Sanja ; Benac, Čedomir ; Mihalić Arbanas, Snježana ; Zidarić, Martin

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts / Vlastelica, Goran ; Andrić, Ivo ; Salvezani, Daša - Split : University of Split, Faculty of Civil Engineering, Architecture and Geodesy, 2013, 63-64

ISBN
978-953-6116-46-1

Skup
4th Workshop of the Japanese-Croatian Project on ''Risk Identification and Land-Use Planning for Disaster Mitigation of Landslides and Floods in Croatia''

Mjesto i datum
Split, Hrvatska, 12-14.12.2013

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
Dubračina River Basin; landslide inventory; airborne LiDAR; landslide causal factors; landslide triggering factors
(Dubračina River Basin; landslide inventory map; airborne LiDAR; landslide causal factors; landslide triggering factors)

Sažetak
Investigations of recent and past landslides in the Dubračina River Basin have been conducted in the aim to define hazard zones, using a methodology for assessing susceptibility and hazard based on local geological and geomorphological conditions. Activities necessary to provide planned landslide susceptibility assessment and hazard analysis include landslide mapping to generate a landslide inventory, followed by mapping of causal and triggering landslide factors (Mihalić and Arbanas, 2012). An overview of the input data required for landslide susceptibility and hazard assessment is given, of which some of the data are in a preliminary phase of preparation. Input data are subdivided into two main groups: landslide inventory map and landslide causal factors. Landslide causal factor encompass two subgroups of data: preparatory causal factors and triggering factors. Almost all of the landslides are situated in the part of a valley being built of siliciclastic rock mass mostly covered by slope deposits. This paper presents preliminary landslide inventory map with data about locations of landslides identified by visual interpretation of LiDAR (Light Detection and Ranging) imagery supplemented by field reconnaissance mapping. The hillshade map was generated with an azimuth of 315° and the sun angle of 45° draped over a bare earth DEM. The slope map was created to characterize the degree of terrain slope and is classified by categories of the slope angles showing the areas of high slope angle in warmer (red, orange, yellow etc.) and areas of low slope angle in cooler (green) colours. Systematic landslide mapping was performed at the area of geomorphological unit of hills within the siliclastic rock mass with total size of 10 km2 (Bernat et al., in press). There are 53 identified landslides. Most of the landslides are clearly visible on LiDAR imagery and there are also landslides for which additional filed checking was necessary for identification. The landslide causal factors present a collection of data that are expected to have an effect on the occurrence of landslides. For derivation of morphological causal factors there is available high precision Digital Elevation Model (DEM) of the investigated area which was derived from the airborne LiDAR data. Geological causal factor will be derived from large scale (1:5, 000) geological map made by Croatian geological survey in 2007. According to genesis of the Dubračina River Basin, it is necessary to derive geomorphological unit map by combination of topographic and geological data. Geomorphological data are presented by the geomorphological map showing different landform units outlined regarding to lithological units, geomorphological features and hydrological conditions. One of the important causes of landslides are also phenomena of excessive erosion described in Aljinović et al. (2010). Erosion map is necessary to depict areas of bad-lands as well as areas where vegetation cover is progressively removing by planar erosion. The stream network and positions of springs are presented in the hydrological map. Land cover map presents different vegetation types distribution according to CORINE (Coordination of Information on the Environment) data base from 2006. Land use map presents types of the land use and also the spatial distribution of settlements, roads and structures. Large scale (1:5, 000) road map was derived by digitizing roads from topographic map HOK (Croatian Basic Map) and it is important as landslide causal map because of high relative importance of roads (e.g., defective construction or maintenance of drainage system) to landslide activation. The landslide triggering causal factors generally have more temporal than spatial importance. This type of data is referred to the rainfall and the earthquake records over sufficiently large time periods. The input data for derivation of rainfall distribution map are precipitation data from the 8 individual meteorological stations. On the basis of preliminary analysis it is known that daily cumulative precipitation is relevant as landslide triggering factor. Spatial distribution of mean annual rainfall amount can only be used as rough indicator of spatial variation of rainfalls quantities which is caused by changes of local relief at small distances. Seismological data are presented as the ground motion acceleration map based on the available national earthquake catalogue. Comprehensive landslide hazard mapping and zonation in the Dubračina River Basin should encompass all the landslide phenomena, including rock fall phenomena in the limestone wall geomorphological unit as well as soil/debris flow phenomena in the hilly area of siliciclastic rock mass. There are also geomorphological units at the investigated area in which development of landslides are not possible (alluvial plane, proluvium). Spatial distributions of geomorphological units is important as a first step in the landslide hazard analysis to define type of geomorphological processes, i.e., landslide phenomena (slide, rock fall, flow) and related erosional phenomena (linear and planar). Landslide frequencies, as indicator of landslide hazard, can only be expressed for particular landslide type per relevant geomorphological unit.

Izvorni jezik
Engleski

Znanstvena područja
Rudarstvo, nafta i geološko inženjerstvo



POVEZANOST RADA


Ustanove
Građevinski fakultet, Rijeka,
Rudarsko-geološko-naftni fakultet, Zagreb