Evaluating physical properties and mechanical parameters of rock slopes and their spatial variability is challenging, particularly at locations inaccessible for fieldwork. This obstacle can be bypassed by acquiring spatially-distributed field data indirectly. InfraRed Thermography (IRT) has emerged as a promising technology to statistically infer rock properties and inform slope stability models. Here, we explore the use of Cooling Rate Indices (CRIs) to quantify the thermal response of a granodiorite rock wall within the recently established Požáry Test Site in Czechia. We observe distinct cooling patterns across different segments of the wall, compatible with the different degrees of weathering evaluated in the laboratory and suggested by IRT observations of cored samples. Our findings support previous examinations of the efficacy of this method and unveil correlations between cooling phases in the field and in the laboratory. We discuss the scale-dependency of the Informative Time Window (ITW) of the CRIs, noting that it may serve as a reference for conducting systematic IRT field surveys. We contend that our approach not only represents a viable and scientifically robust strategy for characterising rock slopes but also holds the potential for identifying unstable areas.

Department of Physical Geography and Geoecology Faculty of Science Charles University 128 43 Prague Czechia

Institute of Geology of the Czech Academy of Sciences Prague Czechia

Institute of Hydrogeology Engineering Geology and Applied Geophysics Faculty of Science Charles University Albertov 6 128 43 Prague Czechia

Institute of Rock Structure and Mechanics Czech Academy of Sciences 5 Holešovičkách 41 182 09 Prague Czechia

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