Evolving slope instability zone at Mt. Turzyna (Sudetes, SW Poland) – An example of incipient deep-seated gravitational slope deformation
Migoń, Piotr; Duszyński, Filip; Kasprzak, Marek; Różycka, Milena
published: Aug 1, 2017
manuscript accepted: Apr 19, 2017
manuscript received: Dec 14, 2016
ArtNo. ESP022006102003, Price: 29.00 €
Abstract In this paper the northern slope of Mt. Turzyna (Sudetes, SW Poland) built of volcanic caprock over sedimentary series is described and explained in terms of deep-seated gravitational slope deformation (DSGSD). Hillslope morphology is consistent with that typical for DSGSD and includes a long and continuous, but low head scarp, back-tilted bench immediately below indicative of sagging, clear bulge near to the toe slope and indistinct lateral boundaries. The entire zone interpreted as DSGSD occupies 0.2 km2, is c. 575 m wide and 380 m long. Electrical Resistivity Tomography (ERT) survey was employed to detect the shearing zone at depth. Vertical offset in the upper slope and resistivity boundaries daylighting in the lower slope have been identified, but a continuous deep-seated structure does not appear. These features suggest an early stage of deformation of the slope, with one continuous shear zone yet to be formed. DSGSD at Mt. Turzyna is neither related to deglaciation, as the area has never been glaciated, nor to direct slope undercutting. It is developing in response to lithostatic stress in favourable lithological and structural settings.