Producing potential hazard map with three dimensional rockfall analysis and design of protection structures: Example of Gümüşhane city center

The central district campus of Gümüşhane province, located on the Trabzon-Erzurum Highway, has steep topography, and because of the climatic and morphological structure, rockfall events that occur frequently in almost every season can cause loss of life and property from time to time. For these reasons, the northern slopes of the centrum of Gümüşhane, which pose a great threat to the rockfall potential, were selected as the study area. In this study, fallen and suspended blocks were identified as well as source rock areas on high steep slopes that threaten residential areas in Gümüşhane city center, and a rockfall inventory map was created by considering the locations of the fallen blocks. Subsequently, rockfall analyzes were carried out using RocPro3D program on the lines determined in the source rock areas with high probability of rockfall. As a result of these analyzes, the spreading distance of the falling blocks, the jump height, the kinetic energies of the rolling rock blocks, and the possibilities of preventing the blocks that may fall with the steel barrier applications were examined. As a result of the analysis, rock blocks rolling from the source rock lines H1, H2, H3, H7, and H9 determined at the upper elevations of the settlements spread in the study area threaten the settlements of Oltanbey District, Hasanbey District, Özcan District, Yeni District and Eskibağlar District, respectively. Rock blocks rolling from the H5, H6 and H8 source rock lines spread between the campuses of Karaer District, İnönü District, Yeni District, Eskibağlar District and Gümüşhane University and source rock areas, respectively, and do not threaten the existing campuses. In addition, rock blocks rolling from the source rock area H4 do not threaten any settlement. As a result of the 3D rockfall analysis, re-analyzes were carried out by applying steel barrier from precaution structures in the settlements under the risk of rockfall, and the most economical and safe different barrier types to eliminate the danger were proposed. The results obtained in the light of all data were evaluated in the ArcGIS computer program, and a potential hazard map showing the conditions before and after the barrier application was produced. Keywords: Geographical Information Systems, Gümüşhane, Potential Hazard Map, Rockfall, RocPro3D, Steel Barrier