With the approximately 50 paroxysmal episodes that have affected the South-East Crater of the volcano since 16 February 2021, Mount Etna has increased its height reaching 3357 meters above sea level
The events that took place in 2021 accumulated significant quantities of pyroclastic material and layers of lava on the cone of the Southeast Crater - the youngest and most active of Etna's four summit craters - leading to a conspicuous transformation of the volcano's shape.
Thanks to the analysis and processing of satellite images, the South-East Crater is now by far higher than its "big brother", the North-East Crater, which has been the undisputed peak of Etna for 40 years.
This historical datum, which has an uncertainty of 3 metres, was obtained by processing two triplet images of the Pléiades satellite acquired on 13 and 25 July 2021, as part of the international partnership Geohazard Supersites and Natural Laboratories (http://geo-gsnl.org/), allowing to update the digital model of the surface of Etna The two groups of acquired satellite images (DSM - Digital Surface Model), produced at a spatial resolution of 1 meter, have been aligned with each other and compared to a 2015 DSM taken as reference model.
Scientists also had to overcome some problems for the correct topographic reconstruction. In fact, to eliminate the effect of the cloud cover, as well as the gas plume emitted from the summit craters, the DSM derived from the July 25 acquisition was integrated with the DSM derived from the July 13 acquisition for the covered southeastern portion from the gas in the summit area.
From the digital model obtained of the terrain it emerges, in a preliminary way, that the highest point of the volcano is now located on the northern edge of the South-East Crater at an altitude of 3357 (± 3 m). This new altimetric data is published in the weekly Bulletin on the volcanic, geochemical and seismic monitoring of the Etna volcano of 10 August 2021 (https://www.ct.ingv.it/index.php/monitoraggio-e-sorveglianza/prodotti-del-monitoraggio/bollettini-settimanali-multidisciplinari)
The summit of Etna, since 1980, has always been considered the North-East Crater which with the paroxysms of September 1980 and February 1981 reached the maximum height of 3350 m. This height, which has decreased over the years due to the collapse of its edges, settled at 2018 meters in the summer of 3326. This primacy, however, has now been surpassed by the cone of the South-East Crater and, today, Etna has a new summit.
Figure: Pléiades images (50 cm spatial resolution) acquired on 13 July 2021 (a) and 25 July 2021 (b) and digital surface model (DSM) of the volcano Etna updated on 25 July 2021 (c).