## 5 Discussion
The DInSAR and integrated data also reveal a slight uplift at lower altitudes on the flanks of the volcano; even though proving impossible to be well constrained and modeled, this information enabled hypothesizing a further and deeper source that was pressurizing during the entire period. As stated before, this eventual deeper source needs more data to be constrained, over larger and different time windows, and is beyond the scope of this investigation. Considering this pulsating behavior of the shallow source, we can postulate that the shallower source (~1.5-2 km b.s.l.) slowly accumulated, before each paroxysm, the same volume of magma lost during each episode (as resulting from HR data inversions). We can use the volume changes modeled and time intervals occurring between two consecutive paroxysms to infer the magma feeding rate from the middle depth (~6 km b.s.l.) to the shallower source, during each quiet phase. We can estimate that the shallow source charged at a rate of about 10 m\({}^{3}\)/s before the second episode, 25 m\({}^{3}\)/s before the third one and about 15 m\({}^{3}\)/s before the last lava fountain (considering a volume not greater than the third one). This gives an average _recharging rate_ of around 16 m\({}^{3}\)/s of magma ascent during the quiet inter-paroysm recharging phases. If we consider instead the total volume depleted from the middle-depth source (6.5 \(\times\) 10\({}^{6}\) m\({}^{3}\)), we can estimate an _overall supply rate_ of about 29 m\({}^{3}\)/s of magma that moved from 6 km b.s.l. to the surface during the entire 2.6-days period, or 31 m\({}^{3}\)/s if we consider the total volume (7.1 \(\times\) 10\({}^{6}\) m\({}^{3}\)) reported by [2]. This mean value (29 to 31 m\({}^{3}\)/s) averages a rate that actually oscillated from the _recharging rate_ of ~16 m\({}^{3}\)/s during closed-vent and non-eruptive conditions (magma moving from 6 to 1.5-2 km b.s.l), to the peak _eruptive discharge rate_ of more than 300 m\({}^{3}\)/s during the paroxysms (considering a mean volume of about 1.8 \(\times\) 10\({}^{6}\) m\({}^{3}\) erupted at each paroxysm in about 90 min). We can perform a very preliminary comparison of this analysis with the last and ongoing (at the time of writing) sequence of paroxysms at SEC (started on 16 February 2021). There is still no precise estimation of the erupted volumes, so we can roughly estimate a total volume of about 45 to 60 \(\times\) 10\({}^{6}\) m\({}^{3}\) erupted during 15 strong episodes occurring from 16 February to 19 March 2021 (based on the very first estimation of the volumes from INGV bulletins available at [[https://www.ct.ingv.it/index.php/monitoraggio-e-sorveglianza/prodotti-del-monitoraggio/bollettini-settimanali-multidisciplinari](https://www.ct.ingv.it/index.php/monitoraggio-e-sorveglianza/prodotti-del-monitoraggio/bollettini-settimanali-multidisciplinari)]([https://www.ct.ingv.it/index.php/monitoraggio-e-sorveglianza/prodotti-del-monitoraggio/bollettini-settimanali-multidisciplinari](https://www.ct.ingv.it/index.php/monitoraggio-e-sorveglianza/prodotti-del-monitoraggio/bollettini-settimanali-multidisciplinari)), accessed on 5 April 2021). Starting from this preliminary information, an _overall supply rate_ of around 17 to 22 m\({}^{3}\)/s can be estimated over the entire month. This rate is comparable to what happened in 2015 and analyzed here, leading to the supposition that the supply mechanism, geometry and rates hypothesized for the 2015 paroxysms can be valid generally for other similar eruptive sequences on Mt. Etna.