THE USE OF DAMAGED SPELEOTHEMS AND IN SITU FAULT DISPLACEMENT MONITORING TO CHARACTERISE ACTIVE TECTONIC STRUCTURES: AN EXAMPLE FROM ZÁPADNÍ CAVE, CZECH REPUBLIC/UPORABA DEFORMIRANIH SIG TER IN SITU MERJENJE PREMIKOV PRELOMOV ZA DOLOCITEV AKTIVNIH TEKTONSKIH STRUKTUR: PRIMER IZ JAME ZÁPADNÍ CAVE, CESKA REPUBLIKA

The EU-TecNet fault displacement monitoring network records three-dimensional displacements across specifically selected tectonic structures within the crystalline basement of central Europe. This article presents a study of recent and active tectonics at Zapadni Cave in northern Bohemia (Czech Republic). It extends previous geological research by measuring speleothem damage in the cave and monitoring displacements across two fault structures situated within the Lusatian Thrust Zone. The speleothem damage reflects strike-slip displacement trends: the WSW-ENE striking fault is associated with dextral strike-slip displacement while the NNW-SSE striking fault is associated with sinistral strike-slip displacement. These measurements demonstrate that, the compressive stress ...1 is located in the NW or SE quadrant while the tensile stress σ3 is oriented perpendicular to σ1, i.e. in the NE or SW quadrant. The in situ fault displacement monitoring has confirmed that, movements along the WSW-ENE striking fault reflect dextral strike-slip while movements along the NNW-SSE striking fault reflect sinistral strike-slip.