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| Titel |
Natural hazards in the Great Caucasus range on the background of climate change - risk maps for the Kazbegi and Mleta areas (Georgia) |
| VerfasserIn |
Tatjana Keller, George Gaprindashvili, Ramin Gobejishvili, Ina Keggenhoff, Mariam Elizbarashvili, Besik Kalandadze, Nino Lomidze, Lorenz King |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077346
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| Zusammenfassung |
| The frequency of mass wasting processes in the investigated area seems to be closely connected with climate change and land use change. In the past decades, especially mudflows occurred more often in the Kazbegi/Mleta region. They may create serious hazards for the population and infrastructure. Our project investigates mass movement events, especially debris flows as depending on topographical, geological, geomorphological, soil and land use conditions.
Selective geomorphological and soil mapping was carried out, and soil samples taken for analysis. The soil map was elaborated in a Geographical Information System (GIS), based on a Digital Elevation Model (DEM), land use data and on a geological map. The land use data were interpreted from satellite information. For the compilation of the risk map, a GIS based simulation of debris flows was used, together with topographical, pedological, hydrological and climatological data (catchment area, elevation, soil depth, soil and land cover classes, precipitation and temperature). The mudflow model used considered the objects of risk (settlements, roads). The risk map may be used for hazard management in the investigated region.
Calculated climate trends show, that recent mean annual air temperature and annual precipitation sums are rising. At the same time, frequency, duration and intensity of extreme precipitation events increase. The relationship between climate elements (temperature and precipitation) and debris flows is shown. Thus, a future increase in hydro-meteorological hazards may be expected.
In Georgia some landslides are triggered by earthquakes, however more than 70% of observed landslide/mudflow phenomena are triggered by the effects of increasing atmospheric precipitation. This index is in direct integral relation with the rate of reactivation of landslide processes. The mechanism of landslides dynamics is defined by the rate of changes in soil water content, which results in variation of consistence features of the subsurface materials, and possibly by lowering the movement persistence up to a critical level in the aeration zone.
Kazbegi and Mleta belong to an extremely complex mountainous area of Georgia according to its geology and the scale and frequency of natural disaster processes. Since the year 2000, the activation of these processes results in increased damage for population, farm lands and engineering facilities that can be observed almost every year. The occurrence intervals are becoming significantly shorter. As a result, more populated areas, engineering facilities and industrial objects have to be included in the risk zones. |
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