Rockfalls in the Duratَn canyon, central Spain: Inventory and statistical analysis

This paper presents an initial analysis of the rockfall processes affecting the walls of the canyon of the River Duratón. This 34 km long meandering canyon in the basin of the River Duero in central Spain (41°18′ N, 3°45′ W) has evolved in a large-scale outcrop of Late Cretaceous calcareous rocks (dolomite and limestone) deformed into a series of asymmetrical folds. Its vertical scarps range from 80 to 100 m; its width varies from 150 to 300 m; and its floor is between 30 and 50 m wide. search consisted of drawing up an inventory of rockfalls from a field survey and mapping the fallen blocks deposited on the basal talus or on the canyon floor, which in turn allowed the original location of each block on the scarps to be identified and located on the orthophotos available. A Digital Elevation Model (DEM) was produced using a Geographic Information System (GIS) and maps made of the aspects and slopes. The aspect of each rockfall data point was determined, and this initial database was completed with other significant parameters (location on the valley side, relationship with the tectonic structure and relative age). An approximate delimitation was also produced of the potential rockfall source area, by reclassifying the slopes according to morphometric criteria. sult is a geomorphic rockfall inventory map, showing the distribution of the rockfalls and a basic statistical analysis to allow a preliminary evaluation of the rockfall characteristics in relation to both their topoclimatic location (aspect) and their structural location (with or counter to the dip of the strata) and to the current geomorphic dynamic through a study of recent scars on the scarps. Recent rockfalls have also been related to the meteorological conditions in which they occurred.