Discolored water appears near Vulcano volcano, Italy
Residents living near Italy’s Vulcano volcano reported the appearance of discolored water in front of Levante Beach on May 22, 2022. The phenomenon started with the appearance of dark and foul-smelling water that soon turned milky-white, as seen in satellite imagery acquired by Sentinel-2.
The phenomenon seems to have reached its peak around 13:00 LT on May 23 and then started to decline sharply, INGV said.1
The duration and extent of the event, as well as the appearance of dark fluids followed by diffuse milky coloring, suggest that an impulsive degassing event has affected the exhalation area facing the Levante Beach.
This area was historically affected by gas emissions from sites present at shallow depths.
The phenomenon of the release of fluids due to pressure increase in the hydrothermal system can cause the emission of sulfides-rich water, present in the shallowest part of the system itself, with typical dark colors.
Subsequent oxidation causes the formation of elemental sulfur and its subsequent massive flocculation, producing the milky-white appearance of the water in the marina.
The impulsive dynamics of the degassing also cause the dispersion of pre-existing deposits of native sulfur, helping to reinforce the phenomenon.
Further investigations of the phenomenon are planned for May 24.
A large increase in the number of low frequency events (VLP; spectral peak less than 1 Hz) was detected on May 22.
The temporal trend of the number of microshocks with a spectral peak > 1 Hz does not show significant variations and there were no earthquakes with magnitudes larger than 1.0 recorded over the past 22 days. No ground deformations have been detected in recent days.
Due to increased activity at the volcano, the Sicilian government declared a state of crisis and regional emergency for the island of Vulcano on November 19, 2021.2
Geological summary
The word volcano is derived from Vulcano stratovolcano in Italy’s Aeolian Islands.
Vulcano was constructed during six stages over the past 136 000 years.
Two overlapping calderas, the 2.5 km (1.5 miles) wide Caldera del Piano on the SE and the 4 km (2.5 miles) wide Caldera della Fossa on the NW, were formed at about 100 000 and 24 000 – 15 000 years ago, respectively, and volcanism has migrated north over time.
La Fossa cone, active throughout the Holocene and the location of most historical eruptions, occupies the 3 km (1.8 miles) wide Caldera della Fossa at the NW end of the elongated 3 x 7 km (1.8 x 4.3 miles) island.
The Vulcanello lava platform is a low, roughly circular peninsula on the northern tip of Vulcano that was formed as an island beginning more than 2 000 years ago and was connected to the main island in about 1 550 CE.
Vulcanello is capped by three pyroclastic cones and was active intermittently until the 16th century. The latest eruption from Vulcano consisted of explosive activity from the Fossa cone from 1898 to 1900.
This volcano is located within the Isole Eolie (Aeolian Islands), a UNESCO World Heritage property.3
References:
1 Vulcano – volcanic activity statement – INGV – May 23, 2022
2 State of crisis and regional emergency declared for the island of Vulcano, Italy – The Watchers – November 21, 2021
3 Vulcano – Geological summary – GVP
Featured image: Copernicus EU/Sentinel-2, The Watchers. Acquired on May 22, 2022
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