Dendrochronological assessment of landslide hazard for the purpose of house construction (An example form Southern Poland)

Abstract

The increasing number of disastrous mass movements creates a growing threat to buildings, roads, etc. In addition, the growing population, mainly in developing countries, causes the colonization of areas endangered by mass movements. One of the most destructive types of mass movements are landslides. Therefore, new methods of estimating landslide risk are currently being sought. The aim of the study was to assess the landslide hazard for the purpose of house construction in a mountain area. We used dendrochronological methods: the analysis of eccentric tree rings. Trees tilted due to landsliding record information about landslide events in their tree rings with annual resolution. Long series of data obtained from tree rings allow us to assess landslide hazard with great precision. The analysis have shown that the studied building plot in Jaszczurowa (southern Poland) and the slope directly above the plot are a subject of active landsliding. Dendrochronology allowed us to detect numerous small landside events on the analysed area. The hazard is related to heavy rainfall events when landsliding on study area can be triggered or accelerated and the ground can then move at a fast rate and on a larger scale. The study shows that any decision to build up the area under analysis will put new houses under the risk of damage due to landsliding.