The TM-71was designed as a manual tool to measure the relative threedimensional movements that occur across adis-continuity separating two adjacent blocks. It remains one of the most precise instruments of its type and more than one hundred are now permanently installed across the globe in order to records low moving fault displacements or slope deformations (e.g.
Stemberk et al.,2010; Klimes et al.,2012). The instruments are commonly installed in caves to minimise the effects of diurnal and seasonal climatic oscillations (e.g.
Briestensky et al.,2011a, b). The data are normally recorded at each site once a month using photographic paper or a digital camera and these images are then interpreted later by the individual investigator.