Structure of the Kutiště rockslide developed in crystalline rocks of the Hrubý Jeseník Mts.

Slope failures developed in crystalline rocks of the Hrubý Jeseník Mts. (Czechia) are quite sparse phenomenon. So far, only a few deep-seated landslides have been described from areas near Keprník Mt. and Červená hora Mt., while shallow flood- related flows are more frequent. The newly identified Kutiště rockslide (GPS 50.1437297N, 17.0563289E) is located in the village of Jindřichov (Šumperk District, the Olomouc Region, Czechia) about 1 km northeast of Štolný hřbet Mt. (883 m a. s. l.) within the Hrubý Jeseník Mts. The rockslide has been geomorphologically mapped and structural analysis and geophysical measurements using electrical resistivity tomography have been carried out to interpret surface and subsurface structure of the landslide. It is a planar rockslide developed in biotitic orthogneiss of the Keprník Nappe, covering an area of approximately 0.13 km2 (ca. 500 × 250 m) with a total altitude difference of about 140 m. The landslide is dominated by a morphologically very distinct amphitheatre-like headscarp. The approximately 300 m long and relatively compact transport zone of the slide is dissected by several transverse fissures and tension cracks, and it is delimited towards the bedrock by a planar sliding surface at depths of 10–17 m. The accumulation part of the landslide, about 150 m long, has further collapsed by gravity. The resistivity image in this part indicates a sliding surface at a depth of about 25 m. The structural data indicate that the slope failure was structurally predisposed by an orthogonal system of longitudinal (NNW-SSE) and transverse (ENE-WSW) brittle structures, and the hillslope-conformal metamorphic foliation of orthogneiss inclined at an angle of 11° towards N to NNW. The resistivity image of the rockslide does not exclude the presence of deeper sliding surfaces throughout the entire extent of the slope deformation, which would enable its further development. The morphologically fresh appearance of the landslide is not necessarily a result of low age, but rather of the strong resistance of the orthogneiss to weathering.