ABSTRACT: Rockfall is defined by Varnes (1978) as a type of instability in which rock blocks released from rock masses

on steep slopes and move at high speed down along the slope. The rock block releases from the source point moves

downward along a trajectory until its energy is extinguished. In deterministic approaches, a large number of physical

and mechanical parameters of both slope surface and block, are used as inputs, and therefore the results are closely

related to accuracy of this number of input parameters. As a reflection of this, empirical approaches, which have

a very high practical value, are preferred especially in the preparation of rockfall maps on regional scale. The

cone propagation approach proposed by Jabodeyoff and Labiouse (2011) is a practical method for regional scale

and stands out among other empirical approaches due to uses only source area map and digital elevation model

(DEM) as input parameters. In this study, in order to test this method various field studies were carried out in

Kargabedir rockfall area based on the principle of determination of possible propagation zone on DEM. In the

field studies carried out at Kargabedir Hill, high resolution aerial photos of the region were taken using a Dron

(unmanned aerial vehicle-UAV) to obtain a high resolution DEM. Thus, a high-resolution (40 cm/pixel) DEM and

a very high resolution (5 cm/pixel) orthorectified aerial image were generated for the area. Propagation zone maps

of Kargabedir rockfall area were prepared for different energy line angle values using high-resolution DEM with

cone propagation approach. In addition, the positions and dimensions (height/length/width) of the fallen blocks were

measured in the region. The dimensions and positions of the fallen blocks were also determined from the orthophoto

and their compatibility with the site measurements was examined. It has been observed that width-length-height

measurements of the fallen blocks acquired from the field and orthophoto are compatible.