Most of the studies devoted to improving our knowledge on the preparative phases of earthquakes have been based, until now, on the study of single (seismological, geochemical, biological, etc.) observables. A large scientific literature documents the occurrence of anomalous space-time transients of such parameters, which are apparently linked to earthquake preparation phases (see for instance Cicerone et al., 2011; Jiao et al., 2018; Tronin, 2006). However, no demonstration is given concerning the possibility of transforming such observations in methodologies that are actually effective (in terms of precision and reliability of the prediction) in the context of an Operational Earthquake Forecast (OEF) system (see also Geller, 1997, and references therein). A multiparametric probabilistic approach, devoted to improving the quality of short-term forecast of seismic hazard (rather than providing exact prediction of future earthquakes), today seems the most promising perspective (e.g., Genzano et al., 2020; Tramutoli & Vallianatos, 2020). To this aim, preliminary studies devoted to qualifying the "predictive" potential of each candidate parameter are of fundamental importance. Starting from long-term correlation analyses, they could provide for each considered parameter the occurrence probability P(Δt, Α, Μ) of an earthquake of magnitude > M within a well-defined region A and period of time Δt. On this basis, the weight to attribute to each parameter within a multiparametric system, devoted to dynamically estimating seismic hazard, could be determined. Such a kind of study should investigate the whole data set of the observations, equally addressing achieved successful rates (i.e., how many anomalies are followed by earthquakes), as well as false-positive rates (i.e., how many anomalies are not followed by earthquakes).