Structure and dynamics of deep-seated slope failures in the Magura Flysch Nappe, outer Western Carpathians (Czech Republic)
- 1Czech Geological Survey, branch Brno, Leitnerova 22, 658 69 Brno, Czech Republic
- 2Institute of Geological Sciences, Faculty of Science, Masaryk University, Kotlarska 2, 612 00 Brno, Czech Republic
- 3Geological Institute of Czech Academy of Sciences, Rozvojova 135, 165 00 Prague, Czech Republic
- 4Kolej Consult & Servis, s.r.o., Krenova 35, 612 00 Brno, Czech Republic Republic
Abstract. Deep-seated mass movements currently comprise one of the main morphogenetic processes in the Flysch Belt of the Western Carpathians of Central Europe. These mass movements result in a large spectrum of slope failures, depending on the type of movement and the nature of the bedrock. This paper presents the results of a detailed survey and reconstruction of three distinct deep-seated slope failures in the Raca Unit of the Magura Nappe, Flysch Belt of the Western Carpathians in the Czech Republic. An interdisciplinary approach has enabled a global view of the dynamics and development of these deep-seated slope failures. The three cases considered here have revealed a complex, poly-phase development of slope failure. They are deep-seated ones with depths to the failure surface ranging from 50 to 110m. They differ in mechanism of movement, failure structure, current activity, and total displacement. The main factors influencing their development have been flysch-bedrock structure, lithology, faulting by bedrock separation (which enabled further weakening through deep weathering), geomorphic setting, swelling of smectite-rich clays, and finally heavy rainfall. All of the slope failures considered here seem to have originated during humid phases of the Holocene or during the Late Glacial.