## 3 Results
### Tiltmeter Results  
In our study, we first assessed whether the ground deformation generated by earthquakes and recorded by tiltmeters exhibited tilting patterns according to established or recurring directions. Furthermore, we tested whether the tilt could be calculated directly from the static displacement estimated from seismic data. Finally, we compared it with that directly recorded by the four borehole tiltmeters placed at various elevations and distances from the crater. We used the signals acquired during the three-years period 2018-2020, selecting two-time windows of 24 h and 240 h for each earthquake, centered on each of the seismic events, in order to study the kinematics of deformation over two different time scales, a short one (1 day) and a long one (10 days). We then proceeded to calculate 24 \(\times\) 4 plots of the tilt vectors (one plot per earthquake and per tilt station) for both 1- and 10-day time windows. Each daily plot represents the ground tilts that are due to the response of the terrain to periodic oscillations mostly induced by lunisolar attraction (tides), but also to the strain to which the site-station is subjected during an earthquake. We focused our study on finding a possible relationship between the tilting direction observed at the stations over a longer period of time and the pattern of static displacement. For this purpose, we analyzed the tilt signals by extracting the long-term trend, estimated by calculating the arctangent of the ratio between the NS and EW components filtered with a third-order polynomial, over a 10-day window including each seismic event, and checked whether this direction was consistent with the displacement. The two observables, displacement and tilt trend, were considered to be consistent if the trend vector pointed toward the closer relative minimum of the static displacement field with a maximum deviation of 45\({}^{\circ}\). The results obtained show that, on average, the stations closest to the epicenters present deformation patterns (inclination of the ground in correspondence with the tiltmeter stations) during earthquakes consistent with the long-term tilt direction (Table 3). In Figure 5 we show an example of a comparison between the seismic static deformation, whose values are expressed according to the color bars, and the long-term tilt direction (blue arrow) measured by IMB tiltmeter. In this case, the co-seismic ground inclination is toward NW (from red values towards colder color values), according to the direction of the tilt vector (W). Moreover, we applied the Equation (3) to two selected earthquakes (2018/04/26 and 2019/05/18, which show compatibility between the seismic static displacement and long-term tilt direction during these two events, see Table 3) to formally calculate the static displacement derivative, and we found a good agreement with the measured tilts, since the deviation between them is always smaller than the amplitude of the tiltmeter signal. In Figure 6 we show the results for 2019/05/18 VT as example. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{2}{c}{**Earthquakes**} & **Depth (km)** & **MD** & **IMB** & **CMT** & **TRC** & **CMG** \\ \hline
1 & 20180426 & \(-\)0.30 & 2.1 & LTC & LTC & TF & TF \\
2 & 20180509 & \(-\)0.55 & 2.3 & LTC & LTC & TF & TF \\
3 & 20180522 & 1.60 & 2.3 & LTC & NC & LTC & TF \\
4 & 20180816 & \(-\)0.45 & 2.2 & No VT and Tilt data & No VT data & No VT and Tilt data & No VT data \\
5 & 20181016 & \(-\)0.70 & 2.5 & No Tilt data & LTC & TF & TF \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The table shows the coherence (LTC) or inconsistency (NC) between tilting direction for each earthquake and tilt station calculated over 10-day windows and the displacement pattern. LTCs were observed in 72% of earthquakes at IMB, 69% at CMT, 36% at TRC and 22% at CMG, while earthquakes were too far (TF) from stations in 11% of cases at IMB, 13% at CMT, 59% at TRC and 74% at CMG. Figure 5: _Cont._