Mount Etna’s Submerged Flank Movement Raises Scientific Concern — What a 4-Centimeter Shift Really Means for the Mediterranean
Scientists monitoring Mount Etna, Europe’s most active volcano, are closely studying new data showing that part of the volcano’s southeastern flank beneath the Mediterranean Sea has shifted by approximately four centimeters over an eight-day period. While the movement itself is small in absolute terms, its speed and location have drawn heightened attention from geologists, volcanologists, and civil protection authorities across southern Europe.
The development does not mean a tsunami is imminent. However, it does underscore a long-recognized geological vulnerability beneath Etna—one that researchers have been studying for decades and that requires careful, measured monitoring rather than alarm.
This article explains what scientists have observed, why the movement matters, what risks are realistically being considered, and what authorities are doing next.
A volcano with a hidden underwater dimension
Rising more than 3,300 meters above sea level, Mount Etna dominates eastern Sicily. What is less visible to residents and visitors is that the volcano does not end at the shoreline. Its southeastern flank extends beneath the Ionian Sea, forming a vast underwater slope made up of volcanic rock, ash, and sediment accumulated over thousands of years.
This submerged flank has long been known to move slowly. Gravity, magma pressure from below, regional tectonic forces, and frequent small earthquakes all contribute to gradual deformation. In geological terms, Etna behaves less like a rigid cone and more like a massive structure that subtly “spreads” outward over time.
What scientists are watching now is not the existence of movement—but the rate of that movement.
What the latest measurements show
Researchers from Italian National Institute of Geophysics and Volcanology have been using seabed instruments, satellite data, and underwater pressure sensors to track deformation beneath Etna’s southeastern flank. Recent readings indicate that a section of the submarine slope shifted about four centimeters over eight days.
In isolation, four centimeters is not dramatic. Buildings settle by similar amounts over decades. But in geology, speed matters. Movements that normally unfold over months or years appearing within days prompt closer scrutiny.
Dr. Lucia Romano, a volcanologist working in eastern Sicily, explained the concern in simple terms: when a system that typically moves slowly shows signs of acceleration, scientists must determine whether that acceleration will stabilize—or continue.
“We are not talking about a collapse,” she emphasized. “We are talking about behavior that needs to be understood in real time.”
Why the southeastern flank is closely watched
The southeastern flank is structurally important. It acts as a stabilizing mass for part of the volcano, counterbalancing pressure generated by magma rising through Etna’s interior. If movement in this area were to accelerate dramatically or fail suddenly, large volumes of material could shift downslope.
In rare scenarios, rapid submarine landslides can displace seawater. This is where tsunami discussions enter the picture—not as predictions, but as theoretical risks that emergency planners must account for.
Scientists stress that such a scenario would require much larger and faster movement than what has currently been observed.
Historical context: Etna and underwater landslides
Etna’s geological history includes periods of major reshaping. Over tens of thousands of years, parts of the volcano have collapsed, rebuilt, and shifted. Some studies suggest that ancient submarine landslides in the Mediterranean were capable of generating localized waves.
However, these events occurred on timescales and magnitudes far beyond the current observations. Modern monitoring allows scientists to detect subtle changes long before they become dangerous.
Professor Marco De Santis of the University of Palermo notes that this is precisely why the current data matters.
“The fact that we can measure centimeters of movement beneath the sea is a success of science,” he said. “It gives us time—time to analyze, time to prepare, and time to avoid surprises.”
Reports from the coast: what residents are experiencing
Along the Sicilian coast near Riposto and Catania, some fishermen have reported unusual currents and minor underwater vibrations. Such observations are being documented but are not uncommon in tectonically active regions.
Authorities caution against drawing conclusions from isolated experiences. The Mediterranean is influenced by tides, weather systems, shipping activity, and seismic micro-events, all of which can affect local water behavior.
So far, no abnormal wave patterns or sea-level anomalies consistent with landslide-induced displacement have been confirmed.
Tsunami risk: separating science from headlines
The word “tsunami” understandably causes fear. Scientists use it cautiously.
For a tsunami to occur from Etna’s flank, several conditions would need to align: a sudden, large-scale collapse of underwater material, rapid displacement of water, and favorable propagation conditions across the basin.
Current measurements show slow deformation, not sudden failure.
Emergency planners in Italy, Malta, and other Mediterranean countries regularly include volcanic flank instability in long-term hazard assessments. This does not mean an emergency is unfolding—it means preparedness frameworks already exist.
Civil protection agencies emphasize that no evacuation orders have been issued, and no immediate danger has been identified.
How scientists are responding
In response to the recent acceleration, INGV has intensified monitoring efforts. These include:
- Additional seabed pressure sensors to detect subtle water displacement
- High-resolution satellite radar to track surface deformation
- Continuous seismic analysis to identify micro-earthquakes
- Submarine sonar mapping to assess slope stability
The goal is not to predict disaster headlines, but to understand whether the observed movement represents a temporary adjustment or part of a longer-term trend.
Researchers are also examining how recent minor eruptions and regional earthquakes may be interacting with the submarine slope.
Shipping and maritime precautions
As a precautionary measure, maritime authorities have adjusted shipping routes near sections of the southeastern coastline. These steps are standard safety practice when underwater instability is being evaluated.
Such restrictions are designed to reduce navigational risk, not to signal imminent danger. Commercial ports remain operational, and no disruptions to coastal life have been reported.
The Mediterranean perspective
One reason Etna’s underwater behavior draws attention is geography. The Mediterranean is a semi-enclosed basin with densely populated coastlines. Cities across southern Italy, Sicily, Malta, North Africa, and parts of the eastern Mediterranean share interconnected waters.
Because of this, scientists take even low-probability risks seriously. Regional cooperation allows data sharing and coordinated response planning, ensuring that no single country monitors potential hazards in isolation.
What residents should—and should not—do
Authorities advise residents to stay informed through official civil protection channels and to avoid relying on social media speculation. Preparedness does not mean panic.
General coastal safety guidance remains unchanged:
- Know local evacuation routes
- Pay attention to official alerts
- Avoid spreading unverified claims
At present, daily life continues as normal across Sicily and neighboring regions.
A reminder of how science works
Events like this highlight how modern geoscience operates. Rather than reacting after disasters occur, scientists now track slow, hidden processes beneath land and sea. They analyze patterns, test models, and communicate uncertainty honestly.
Four centimeters of movement does not equal catastrophe—but it is data. And data, when interpreted carefully, reduces risk rather than amplifies fear.
Mount Etna has always been dynamic. What has changed is our ability to listen to it.
Looking ahead
In the coming weeks, researchers will determine whether the southeastern flank’s movement stabilizes, slows, or continues at an elevated rate. Each outcome carries different implications, and all are manageable within existing monitoring frameworks.
For now, experts emphasize vigilance, not alarm.
Etna remains active, complex, and closely watched—both above and below the sea. The current findings serve as a reminder that even familiar landscapes hold processes still unfolding, often quietly, beneath the surface.
Science’s role is to observe those processes calmly, communicate them responsibly, and ensure that preparedness keeps pace with understanding—not with fear.