## 4 Results
### Correlation of MS Events with Environmental Factors
The amplitude of temperature ranges was then computed for each cooling ramp as the difference between the maximum daily temperature and the subsequent minimum, while for heating ramps they were computed in the opposite way (Figure 11b). Furthermore, the mean rate of rock mass heating and cooling ramps was computed by dividing their amplitude by their duration (Figure 11c). Figure 10: Comparison between the temporal evolution of MS events and environmental factors at the Acuto field laboratory: cumulative number of MS and false events computed over the entire monitoring period (**a**); daily maximum–minimum rock temperature (red and blue lines) and cumulative rainfall (green line) (**b**); daily and cumulative number of MS events (**c**). Four time intervals (P1–P2–P3–P4) are highlighted in all plots representing the periods in which the highest increments in both MS and false event occurrence were observed. Gray areas in panels (**a**,**c**) represent periods in which the MS monitoring network was not working due to power supply interruptions. MS events show a clear differentiation in their distribution between the heating and cooling phases, with 111 and 153 MS events, respectively. In more detail, during the 4-day freezing period of February 2018, 69 MS events occurred in correspondence with an increasing temperature regime (i.e., heating phase), while only 14 of them were recorded during a regime of decreasing temperatures, meaning that 63% of all MS events that occurred during cooling phases were clustered during this extreme meteorological transient. Figure 11: Comparison between the distribution of MS events (**a**), daily thermal ranges (**b**), and mean daily temperature rates (**c**). In each plot, the distinction between the heating (in red) and cooling (blue) phases of the rock mass is proposed with a view to investigate the response of the jointed rock block to different thermal regimes of increasing (heating) or decreasing (cooling) temperatures. Gray areas in panel (**a**) represent periods in which the MS monitoring network was not working due to power supply interruptions. The magnitude of temperature ranges of heating and cooling ramps is comparable, also showing a significant variability throughout the entire period, but the average rates of heating ramps are consistently higher than the cooling ramps. On the contrary, if excluding the period characterized by not-common weather conditions (i.e., the winter storm), the microseismicity tends to be concentrated during the cooling phases of the rock mass, as also highlighted by the different trends in their cumulative curves (Figure 11a). However, since the MS dataset is affected by several month-long gaps, the comprehension of the relationship between thermal boundary conditions and the local microseismicity is difficult to discern. MS events show a very discontinuous distribution during the whole monitoring period with a limited number of short time windows in which a significant concentration of MS events is recorded. For this reason, a detailed investigation of three distinct periods characterized by the highest MS event peaks was performed. These periods were selected as they were also representative of different climatic and meteorological conditions. For each time window, the comparison between rainfall intensity, temperature fluctuations, and MS event distribution was performed with a view of highlighting the influence of highly variable environmental conditions on the potential acceleration of fracturing processes (Figure 12). The first period comprises a time window spanning from 23 February 2018 to 14 March 2018 when, as previously introduced, the quarry area experienced an unprecedented weather event (Figure 12a-c). In this period, the most intense MS activity is clustered in four days characterized by a marked temperature drop that caused freezing conditions and by a small amount of cumulated rainfalls (Figure 12a). MS events seem to be better correlated to temperature variations rather than to rainfalls.