Etna update, 16.06.2023
Etna remained quiet last week as well. However, increasing inflation and gas emissions, as well as a slight increase in tremor, could be the first signs of an imminent eruption.
Clouds continued to frequently hinder observation of the summit craters via webcams last week. During the cloud-free hours, intense gas emission was observed at Bocca Nuova, which was occasionally intensified in a pulse-like manner. At the Southeast Crater Complex, steam was emitted persistently from the area of the large breach respectively the crater between the old and the new Southeast Crater. From the northeastern to northern summit area of the New Southeast Crater, fumaroles released gas and steam persistently. On the other hand, Voragine and Northeast Crater continued to emit only minor amounts of gas.
The evaluation of the data from the GPS stations showed an increase in the inflation of the volcanic edifice in the area of the central mountain flanks for the period between 5 and 11 June. This put an end to the persistent slight deflation that had been going on for several months [1].
The signals from the clinometric stations showed no significant changes for the period between 05 and 11 June [1].
The measurement of infrasound activity at the summit craters was affected by strong winds in the period between 05 and 11 June. The number of events was at a similar level as in the previous week. The amplitude of the events was low. The source was mainly Bocca Nuova [1].
Sulphur dioxide emissions at the summit craters were at a medium level during the week of 05 June to 11 June, subject to an increasing trend.
Ground carbon dioxide emissions (ETNAGAS station) increased significantly during the same period and moved towards a high level [1].
The online seismograms of station ECNE were only available again last week from 14.06. and showed only weak noise.
The tremor moved at a medium level last week and was subject to a slightly increasing trend [2].
From 5 to 11 June, the source of the tremor was below the southeast crater at a depth between 2500 and 2800 m [1].
On 15.06. an earthquake of magnitude 1.7 occurred southwest of Rifugio Citelli (east/northeast flank). On 16.06. an earthquake of magnitude 2.5 was registered near Santa Venerina (east flank) [3].
My interpretation of the data and speculation about further developments:
The increase in the inflation of the volcano edifice, as well as the increased emissions of carbon dioxide, indicate that more magma is rising in the mountain at the moment. The tremor has also increased slightly, which indicates that magma is in motion. Presumably, these are moderate amounts that can probably be stored in the mountain for the time being. Sooner or later, however, there will probably be another eruption. But it is difficult to say when this will be the case. The character of the eruptive activity cannot be predicted either. It is possible that the magma that is now rising will first degas slowly and then, in a few months, there will be an effusive and prolonged eruption, as in November 2022. However, if there is a larger amount of fresh magma, there may also be strombolian and effusive activity at the Southeast Crater complex. However, it is also possible that, as in May, a paroxysmal episode suddenly occurs at the Southeast Crater complex, resulting in a brief but very explosive eruption. At the moment, however, nothing points to an imminent eruption. In any case, the mountain is always good for a surprise!
1 - INGV-Sezione di Catania. 2023.Etna - Bollettino settimanale, 05/06/2023 - 11/06/2023
2 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.
