Vulcano volcano (Aeolian Islands, Italy) - Smithsonian / USGS Weekly Volcanic Activity Report for 29 September-5 October 2021 (New Activity / Unrest)

INGV reported that hydrothermal activity at Vulcano increased in July, and notably more in September. Specifically, temperatures of the fumaroles on the crater rim and on the inner flank had increased along with the amounts of carbon dioxide and sulfur dioxide in the emissions. The highest temperature of 340 degrees Celsius was along the rim.
The temperature and salinity of groundwater measured near the base of La Fossa cone were both elevated, and outgassing from ground sites was noted. On 13 September the seismic network detected a significant increase in microseismcity linked to hydrothermal processes. Additionally, very-long-period events were also recorded for the first time in 15 years when instrumentation able to detect the signals was installed.
Deformation on the N side of the cone was first identified in mid-August and totaled 1 cm of uplift by mid-September. The report stated that new seismic stations and instruments to measure carbon dioxide emissions had been added to the monitoring network, and a thermal camera pointing at the fumarolic field was planned. The Dipartimento della Protezione Civile raised the Alert Level to Yellow (the second lowest level on a four-color scale) on 1 October.

Sources: Sezione di Catania - Osservatorio Etneo (INGV), Dipartimento della Protezione Civile
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From: Global Volcanism Program, 2021. Report on Vulcano. In: Mayberry, G (ed.), Weekly Volcanic Activity Report 29 September-5 October 2021. Smithsonian Institution and US Geological Survey.