Etna, Sicily, Italy, 18 September 2026 Much of what INGV measures on Etna looked subdued in the week to 13 September. Tremor amplitude stayed between low and medium. One earthquake reached magnitude 2, a 2.3 near Monte Nero. The GNSS and tilt networks showed no significant change, sulphur dioxide fell back towards mid-range values, and satellite thermal output peaked at about 7 megawatts on 8 September. Not every instrument agreed. Infrasonic event rates ran high to very high on 8 September, with sources at the Northeast Crater, the soil radon network recorded very strong positive anomalies at its southern-flank sites during the first week of the month, and the last helium isotope sampling, on 26 August, was in the high range. The summit, meanwhile, went on emitting ash almost continuously. The Northeast Crater has been the source of it, pulsing ash to roughly 4,000 metres and dispersing it out of the summit area to the east and south. Bocca Nuova joined in on 7 and 8 September from its BN1 vent. The South-East Crater and the Voragine, which between them produced most of the summer's activity, have been doing little except degassing through their fumaroles. Modest ash at approach height with a southerly drift is what closes an airport. INGV raised the aviation colour code to red early on 14 September with the cloud estimated at four kilometres and moving south. Catania shut sector C1 and suspended arrivals from 09:30 until 16:00, extended that at 13:15 to 22:00 with sector B3 closed as well, then extended it again that evening to ten the following morning. Sixteen flights operated without restriction all day. By the evening of the 14th more than 150 had been cancelled or rerouted. The suspension was pushed out again on the 15th to 14:30, and by one o'clock that afternoon 80 flights had been cancelled, 25 arrivals and 55 departures, with another 44 reorganised through Palermo, Comiso, Trapani and Fiumicino. As of 17 September the aviation code remained red, Fontanarossa was operating normally, and ash emission was continuing towards the south. Vulcaniya | Volcanoes • People • Planet