1. Monitoring and physical model simulation of a complex slope deformation in neovolcanics in neovolcanics J. R y b á ř & B. K o š ť á k Institute of Rock Structure and Mechanics Czech Academy of Science Prague, Czech Republic

2. Čeřeniště landslide – the main scarp

3. Čeřeniště slide - upper part displays individual blocks separated by deep trenches

4. 1- scarps and trenches in basalt rocks 2 - recent potential and old landslides 3 – recent active landslide 4 - outstanding edges in the relief 5 - erosional walls 6 - debris 7 - alluvial sediments 8 - spring 9 - lake 10 - undrained depressions 11 - waterflow 12 - periodically dry creek Čeřeniště slide – situation of slope deformations

5. Strange tilted platform with a lake The Labe River Canyon 2km: 140 m a.s.l. Čeřeniště slide - g Čeřeniště slide - geological cross-section through the slope deformation C r o s s s e c t i o n:

6. Engineering-geological maps - scale 1:2 000, 1:5 000 - geomorphological and geological maps 1:10 000 - series of longitudinal and transversal profiles Monitoring of deformation effects - two highly sensitive mechanico-optical dilatometric gauges TM71 in the trenchesunder main separation wall Applied geophysics - three phases:- symmetrical resistance profiling and vertical electrical probing - spontaneous polarisation SP - radiometry Geomorphological investigations - to find relation between the evolution of the Labe River valley and Čeřeniště slope deformations Geological and Quarterly-geology methods and dendrochronology Photoplastic physical models - to verify the solutions I n v e s t i g a t i o n m e t h o d s: I n v e s t i g a t i o n m e t h o d s:

7. Čeřeniště slide - 3D field deformation monitoring in scarps using TM71

8. M o n i t o r i n g:M o n i t o r i n g:M o n i t o r i n g:M o n i t o r i n g: Low value angular deviations registered provide evidence of block arching in scar zone Displacements registered at the upper part of Čeřeniště deformation Component z represents progressive sinking of rock blocks into the main scar trench No separation of rock blocks indicated

9. P h o t o p l a s t i c m o d e l s: made of agar gels: made of agar gels: agar deforms progressively by body weight after horizontal sidewise stress release models are observed in polarized light models are observed in polarized light models produced as a series of individual elastoplastic, brittle layers with slippery plastic intercallations models produced as a series of individual elastoplastic, brittle layers with slippery plastic intercallations following model is simulating a series of basalt lava flows with tuff intercallations in a deformation process of gravitation tectonics induced by deepening of the Labe River Canyon following model is simulating a series of basalt lava flows with tuff intercallations in a deformation process of gravitation tectonics induced by deepening of the Labe River Canyon the erosion process took place in Pleistocene when volcanites were cut through completely up to the Cretaceous basement - the Labe River reached then a level of up to 16 m beneath the present bottom (140 m a. s. l.) the erosion process took place in Pleistocene when volcanites were cut through completely up to the Cretaceous basement - the Labe River reached then a level of up to 16 m beneath the present bottom (140 m a. s. l.)

10. P h o t o p l a s t i c m o d e l Upper scar area of the Čeřeniště landslide produced in one of the models Morphology shows: separation wall deep scar inclined sinking blocks trenches in the marginal zone (right) voids under the hill (left)

11. P h o t o p l a s t i c m o d e l platform formation complex layered model representing a series of lava flows deepening of the Labe River Canyon formation of wedge-like islands separated by anticlinal shear planes after horizontal stress release the wedge-like islands are almost stress free chance for undisturbed platforms to develop and survive in the heavily deformed slope

12. Model 30: Evolution in a system of volcanic lava flows after a unilateral deformation release due to the Labe River erosion model time: 0:10:00 P h o t o p l a s t i c m o d e l

13. Model 30: Superficial block morphology in the scar area due to continuing evolution in the system of lava flows in the unilatreal release process due to the Labe River erosion model time: 0:30:00 P h o t o p l a s t i c m o d e l

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17. The END......thanks for your attention!