DEBRIS FLOW ACTIVITY RECONSTRUCTION USING DENDROGEOMORPHOLOGICAL METHODS. STUDY CASE (PIULE IORGOVANU MOUNTAINS)

Abstract

Debris Flow Activity Reconstruction Using Dendrogeomorphological Methods. Study Case (Piule Iorgovanu Mountains). Debris flows are one of the most destructive mass-movements that manifest in the mountainous regions around the world. As they usually occur on the steep slopes of the mountain streams where human settlements are scarce, they are hardly monitored. But when they do interact with built-up areas or transportation corridors they cause enormous damages and even casualties. The rise of human pressure in the hazardous regions has led to an increase in the severity of the negative consequences related to debris flows. Consequently, a complete database for hazard assessment of the areas which show evidence of debris flow activity is needed. Because of the lack of archival records knowledge about their frequency remains poor. One of the most precise methods used in the reconstruction of past debris flow activity are dendrogeomorphological methods. Using growth anomalies of the affected trees, a valuable event chronology can be obtained. Therefore, it is the purpose of this study to reconstruct debris flow activity on a small catchment located on the northern slope of Piule Iorgovanu Mountains. The trees growing near the channel of transport and on the debris fan, exhibit different types of disturbances. A number of 98 increment cores, 19 cross-sections and 1 semi-transversal cross-section was used. Based on the growth anomalies identified in the samples there were reconstructed a number of 19 events spanning a period of almost a century.