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Geomorphology

Volume XIX |

Landslide-susceptibility Analysis, Mapping and Validation in the Bălăcița Piedmont (South-West Romania)

Abstract: This work presents the results of applying the GIS matrix method (GMM) to the mapping and validation of landslide-susceptibility analysis in different sectors of the Bălăciţa Piedmont. The main objective of the paper concerns the achievement of landslide-susceptibility maps based on the inventory, classification and description of the landslides within the study area. The starting point was represented by the DEM and, subsequently, based on the lithological data, other determinant factors were analyzed and reclassified in a vectorial format: slope angle, slope elevation and slope aspect. After the factors that determine instability were identified for each type of mechanism, susceptibility maps were drawn. In the resulting landslide-susceptibility map a model for the validation is presented (based on the determination and calculation of a set of landslides not included in the susceptibility analysis). The landslide-susceptibility maps of the Bălăciţa Piedmont are preventive tools intended to minimize risks in the threatened areas, especially near the settlements that are located on the left slope of the Jiu river and witness the reactivation of old landslides.

Volume XIX |

Assessment of Soil Erosion by RUSLE Model using Remote Sensing and GIS – A case study of Ziz Upper Basin Southeast Morocco

Abstract: cause many environmental and socio-economic problems on -and off-site: loss of biodiversity, reduced productivity of agricultural land, siltation of dams, increased risk of flooding. The quantification of soil erosion is essential in the management and conservation of the soil and water resources. Modeling soil erosion can provide a lot of information to estimate soil loss and sediment yields at large-scale. In this study, the Revised Universal Soil Loss Equation (RUSLE) integrated into a GIS was used to quantify soil losses in the large upper watershed of Ziz (4435 km2) in southeastern of Morocco. The RUSLE parameters were estimated based on data from satellite imagery, DEM-SRTM and national watershed management plan studies. The results show that annual average of the potential soil erosion is 489.5 t. ha-1. yr-1 and the specific sediment yield is 36.4 t. ha-1. yr-1. The main sources of sediment are in the watershed upstream parts and some deposition zones are located before the catchment outlet. These soil losses contribute to the annual siltation of the Hassan Eddakhil dam by a rate of 3.5%. The application of principal components analysis to soil erosion factors shows an important influence of the soil erodibility factor (K) followed by the topographic factor (LS) then crop management factor (C). These modeling results will provide data within the Moroccan southeastern High Atlas that can constitute a road map for future soil erosion projects and it can be a useful tool for proposing soil conservation strategies.

Volume XIX |

The occurrence of the armored mud balls during the flash flood phases of the streams from the Meledic Plateau – the Curvature Subcarpathians, Romania

Abstract: Armored mud balls that form in fluvial environments were observed on the river bed of two small streams from South-East Subcarpathians Bend, in the area of Miocene deposits with salt dia-pirs. Pieces of well-rounded clay mate-rial but with coarse surface were found on the gravel banks as well as partially submerged into stream channel and embedded in soft sediments of stream banks. The surfaces of mud balls, nearly spherical and ranging from 5 cm to 17 cm in diameter, were studded with sand grains and gravel that collected during flash floods as a result of bedload transport. The main source material of the armored mud balls consists of dark clay material detached from the cap rock of the salt massif that is crossed by the two streams. The newly formed armored mud balls, which were found among the gravels on the stream bed following the summer flash flood event from June 2019, supports the fact that these particular sedimentary features form during exceptional floods when pieces of clay material are rolled by the high-energy water flow, which results in acquiring of their spherical shape and the pebble shell. This paper represents the first report on the occurrence of modern armored mud balls formed in a fluvial environment, located in the Curvature Subcarpathians, Romania.

Volume XIX |

Gross chemical analysis of the turf and podzolic soils on glacial deposits, laid by dense carbonate rocks

Abstract: Gross analysis allows us to reveal issues concerning the genesis of soils and to identify the peculiarities of elementary soil processes. The article summarizes the results of the study of gross chemical analysis of the turf and podzolic soils on alluvial and glacial deposits, laid by dense carbonate rocks. Features and relationships of oxides content in soils and soil-forming rocks are considered, that will make possible to justify important issues of the nature of these soils and to study the dependence of their natural properties with dense carbonate rocks.
It is established that oxides of silicon, ferum, aluminum and calcium form the basis of gross chemical composition of the turf and podzolic soils on alluvial and glacial deposits, laid by dense carbonate rocks. The maximum content of the first component is observed in the upper humus-eluvial horizon (90–94%), aluminum and ferum oxides – in iluvial accumulative horizons, where their content in total is 7–15%. Calcium oxide content in soil profile of studied soils, naturally increases from 0.36% in the upper horizons to 0.95% in the transitional, and in the laid carbonate rocks its content can reach up to 35%. This confirms the fact that laid carbonate rocks have a significant influence on the flow of all soil elementary processes, and gross analysis confirmed the presence of carbonates in the entire soil profile, which could not be determined during field or macromorphological studies. Oxides of alkaline-earth metals are mainly accumulated in the upper humus horizons of all soils, their content decreases down the profile. Potassium and phosphorus oxides, although pliable to washing, however are delayed in the soil and included in the biological cycle and partially fixed in secondary minerals. The content of biologically important components such as P2O5, MnO, S, N in the upper horizons of the studied soils is closely related to the accumulation of humus.

Volume XVIII |

Climate parameters relevant for avalanche triggering in the Făgăraș Mountains (Southern Carpathians)

Abstract: The climate conditions may contribute significantly to the generation of several hazards in mountain areas, such landslides, wildfires, flash floods and avalanches. This study examines the variation of the main meteorological parameters with impact on avalanche triggering conditions at Bâlea-Lac Meteorological Station. At the best of our knowledge, this is the first overview of the basic climate parameters which are potentially avalanche triggers in the Făgăraș Mountains (Southern Carpathians). The study is based on data from only one weather station (Bâlea-Lac) from the period 1979-2017, assuming it is consistently relevant from climatic point of view for avalanche occurrence in the area. The results demonstrate that the theoretical circumstances for avalanche triggering (e.g. snow pack, fresh snow or wind) can be captured. This paper briefly describes the nivologic monitoring system run by the National Meteorological Administration and emphasises its utility for avalanche forecasting and alerts.