Investigations Regarding Bear Cave Massif (Lower Silesia) Long-Term Stability

  • Krzysztof Mąkolski Institute of Geodesy and Geoinformatics, Wroclaw University of Environmental and Life Sciences, Grunwaldzka 53, 50-357 Wroclaw
  • Stefan Cacoń Institute of Geodesy and Geoinformatics, Wroclaw University of Environmental and Life Sciences, Grunwaldzka 53, 50-357 Wroclaw
  • Olgierd Jamroz Institute of Geodesy and Geoinformatics, Wroclaw University of Environmental and Life Sciences, Grunwaldzka 53, 50-357 Wroclaw
  • Blahoslav Košták Institute of Rock Structures and Mechanics, Czech Academy of Sciences, V Holešovičkách 41, 841 09, Prague 8
  • Mirosław Kaczałek Institute of Geodesy and Geoinformatics, Wroclaw University of Environmental and Life Sciences, Grunwaldzka 53, 50-357 Wroclaw

Abstract

Bear Cave under Mt ¦nie¿nik is located near the Lower Sile­sian Village of Kletno in a wider tectonic fault zone of Sudeten, Klodzko Valley, South Poland. Stability requirements along the visitor’s path in the cave called for permanent checks of pos­sible rock movements in the massif, while mining operations in the neighbouring marble quarry represented major threat to cave stability. Precise levelling network for vertical movements in the cave and its vicinity was established about 20 years ago. Outside the cave in the Kle¶nica River valley levelling traverses were crossing tectonic faults. Periodical measurements have been repeated since 1984. In the cave two fault zones of major risk have been checked also with TM-71 crack gauges and re­cords have been taken with a month frequency. These two were the tectonic crack zones of the Water Corridor and the main fault structure of the cave found in the Cascade Alley. Fourteen years ago after finding that quarry blasts induced increased movements in the cave, quarry operations were stopped. Re­cently, gradual subsidence of some levelling bench-marks was observed, as well as some periods of increased micro-displace­ments on the tectonic crack zones. Such observations are dis­cussed.

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Published
2008-12-01
How to Cite
1.
Mąkolski K, Cacoń S, Jamroz O, Košták B, Kaczałek M. Investigations Regarding Bear Cave Massif (Lower Silesia) Long-Term Stability. AC [Internet]. 2008Dec.1 [cited 2020May29];37(2-3). Available from: https://ojs.zrc-sazu.si/carsologica/article/view/152
Section
Original papers