## 1 Introduction
In this regard, the development of monitoring strategies devoted to take into account the numerous parameters which control the rock mass behaviour for assessing their influence on the slope stability provides a useful tool to mitigate geological risks [14; 15]. Two methods have been widely used for natural hazard control and for managing the related risks. The first method, more focused on hazards, consists of monitoring the precursors of rock failures by a multi-parametric monitoring system mainly composed of seismic or micro-seismic devices, as well as acoustical emission [16; 17; 18; 19; 20; 21]. The second method, equally focused on hazard and on vulnerability, consists on the observation of landslide source areas as well as of threatened infrastructures by using optical or interferometric devices for detecting fast morphological changes that are hazardous to the monitored infrastructures [22; 23; 24; 25; 26]. Several authors [27; 28; 29] have tried to combine these two strategies by using innovative devices, such as terrestrial laser scanners (TLS) and interferometric radar (GBInSAR), which are capable of inspecting an unstable slope with high spatial and temporal frequency, coupled with microseismic monitoring systems that provide deeper insight into the stress conditions within the rock mass. Multi-parametric monitoring systems devoted to risk mitigation involving strategic infrastructures (such as highways, railway and aqueducts) or workplaces (like mines and yards for underground excavation) are also of great relevance. Important examples can be found in mine work areas, where multi-parametric monitoring systems are installed with the aim of safe and reliable operations in the mining area [30; 31]. To ensure post-mining risk management and public safety, several real-time microseismic monitoring systems and remote sensing networks have been installed to detect the ongoing jointing of rock masses as precursor events of an increasing strain rate that could anticipate slope collapse [32; 33]. Where specific meteorological conditions exist, the surface temperature in outcropping rock masses fluctuates naturally under the influence of local weather conditions and can be sensitive to thermal forcing related to cyclic expansion and contraction that can act over a long time, inducing cumulative deformations. These effects can influence the long-term behaviour of fractured rock masses, operating as a thermal fatigue process [34] and leading the joints of a rock mass to evolve towards failure [12; 35; 36; 37; 38; 39]. Due to daily and seasonal temperature changes [40], rock failures can also occur when impulsive trigger factors (such as precipitation, seismic activity and freezing) are not effective. To address this issue, multi-parametric monitoring systems can be installed to evaluate the influence of thermo-mechanical effects [41; 42; 43] with particular attention to contexts where infrastructures are exposed to geological risk. Remote sensing techniques are, instead, suitable for recognizing the surficial temperature of rock masses through infrared thermography (IRT) applications [44; 45; 46]. Multi-parametric monitoring systems coupled with numerical modelling studies, focused on rock mass temperature and related rock strain, have also been applied for the preservation of relevant sites, also elected as natural heritage [47; 48; 49]. Several approaches have already been proposed in the literature for data analysis. The most widespread conventional approach is, undoubtedly, the deterministic approach (i.e., data-driven analysis), wherein relations among monitored data are physically based. The main fields of application of this approach include among others landslide susceptibility [50; 51], microzonation studies [52], hydrogeology [53], and the study of rainfall-induced shallow landslides [54].