Tension rises on Etna: red alert for aviation and ash towards Catania

Tension is rising on Etna: the alert level for aviation (Vona) has returned to red after the new, intense explosive activity at the Voragine crater, with the volcanic tremor at very high values. An ash fall was reported towards the south-east, in the direction of Catania airport, which reopened only yesterday after nine days of stoppage and over 700 missed flights

Etna is once again a concern. The aviation alert level, Vona (Volcano observatory notice for aviation), rose from orange to red in the evening, after the new and intense explosive activity at the Voragine crater and the volcanic tremor pushed to very high values. Ash fall has been reported towards the south-east, with the cloud moving in the same direction - that of Catania airport - observed by the visible and thermal surveillance cameras of the National Institute of Geophysics and Volcanology, Catania Etna Observatory.

Volcano activity

Effusive activity continues from the vents at 2,750 and 1,990 meters above sea level. The most advanced front of the lava flows stands at around 1,395 metres, between Rocca delle Palombe and Rocca Musarra. Between 09.40 and 12.40 the North-East crater produced a series of short-lived explosions, with a plume of ash dispersed in the summit area towards the South-East. At 6.22pm Strombolian activity resumed at the Voragine and, from 6.45pm, the emission of ash from the North-East crater intensified.

The tremor on the rise

From a seismic point of view, the average amplitude of the volcanic tremor fluctuated throughout the day between low and medium values, growing progressively. In the last few hours the increase has become more marked: from around 6pm the amplitude went from the range of medium to high values. The centroids of the tremor sources are located between the North-East and Voragine craters, at an altitude between 2,800 and 3,000 metres.

The return of the red alert and the uncertainty of flights

The return to the red level is the same condition that, in recent days, had imposed the closure of Catania-Fontanarossa, which only reopened yesterday at 2pm after nine days of blockade. The green light had arrived thanks to the transition of the alert from red to orange and the lower emission of ash, with the reopening of sectors C1 and B3 ordered by the management company Sac. The stop - the most severe for the infrastructure in the last twenty years - had caused the cancellation or diversion of over 700 flights to Palermo and Comiso, in full tourist season, with around 40 thousand passengers per day involved. Now the new surge in activity and the cloud heading south-east bring the airport's operations back into a state of uncertainty.