Santorini, Greece – Seismic activity that shook the Santorini-Antikythera region on Tuesday night was identified by experts as stemming from volcanic forces, not tectonic ones, signaling a rise in magma beneath the island’s surface, according to Professor Costas Synolakis, a leading expert on natural disasters. He called for a broader meeting with international specialists to better assess the ongoing volcanic risks.

“The earthquakes we recorded last night were of a distinct type, signaling that volcanic magma is rising,” Synolakis told ERT. “Although the tremors stopped within about an hour and a half, it was clear that these were volcanic in nature.”

The professor added that the seismic activity was part of what experts refer to as a “volcanic swarm,” which, according to seismologists, produced significant noise, indicating magma movement. “At this point, we need a broader meeting with international experts who have experience in similar volcanic situations,” Synolakis continued. “We can’t rely solely on the experiences of 2011. We need to compare this with dozens of other cases to understand where this might be heading.”

While the recent seismic activity has subsided somewhat, Synolakis stressed that the changing nature of the tremors warranted a reevaluation of the situation. “The quick change in the nature of these tremors – becoming clearly volcanic – means we need to reconsider the phenomenon,” he explained.

Regarding future developments, Synolakis said two potential outcomes are possible: the magma could either form a small volcanic cone or trigger a larger earthquake.

Magma Rising to the Surface

The professor reiterated his earlier assessment that the earthquakes likely have a volcanic rather than tectonic origin. “We are close to a volcano that is in an active phase,” he said. “The shifts and quakes are indicative of magma rising toward the surface, causing the fractures in the earth’s crust.”

Asked whether the phenomenon might subside, Synolakis acknowledged that it could, pointing out that similar events had been observed before. “However, we must also evaluate other parameters, such as ground deformations, measurements of the seabed, and volcanic gases.”

When asked if the activity could persist until Easter, Synolakis said, “Only the Earth knows. If the seismicity continues to decrease next week, we’ll be able to draw more confident conclusions.”

A New Phase for the Volcano

The harmonic seismic tremors that had indicated potential volcanic disturbance in Santorini ceased as abruptly as they had begun on Tuesday night, leading experts to wonder if the volcano was “falling back asleep.” However, Luis Donoso, a geophysicist from the University of Chile, said it was more likely that the volcano was entering a new phase of activity.

“It’s not so quick to fall asleep – it’s just entering a new phase,” Donoso explained.

The night’s seismic activity was particularly intense for the scientists studying the sequence. After a brief 12-hour period of quiet, the Santorini seismograph began recording harmonic tremors, indicating movements of volcanic fluids within fault lines. These tremors had the distinct sound of magma moving, a phenomenon the European-Mediterranean Seismological Centre referred to in its reports.

Athanasios Ganas, Director of Research at the Geodynamic Institute, confirmed that numerous small tremors were recorded in Santorini’s seismographs between 8:00 and 9:30 PM, which likely stemmed from the movement of volcanic fluids.

These tremors stopped and resumed several times, prompting concerns that the volcano might be “building pressure” or “falling back asleep,” similar to the events of 2011 when similar tremors were recorded without leading to a volcanic eruption.

A Return to Normalcy, for Now

By 3:37 AM, the Geodynamic Institute recorded a weak earthquake of 4.0 magnitude, centered 16 kilometers southwest of Amorgos. This earthquake followed the harmonic tremors, signaling a return to normal seismic conditions.

Monitoring Ongoing Volcanic Activity

Meanwhile, geologists caution against jumping to conclusions about an imminent eruption. Professor Evthymios Lekkas of the University of Athens explained that the “buzzing” sounds reported earlier were more likely due to surface processes than the earthquake itself, caused by the dispersion of sound waves rather than seismic activity.

Experts are urging calm, as predicting volcanic eruptions is notoriously difficult. George Vougioukalakis, a volcanologist and member of the National Committee for Monitoring Active Volcanoes, told protothema.gr that the current seismic activity is part of a longer ongoing process. “What we’re seeing now is a repetition of what occurred in 2011, with slight increases in the caldera’s surface. The volcano may ‘sleep’ again, just as it did in 2011.”

The recent seismic activity is considered part of a natural, ongoing geological process. “Volcanoes are the breathing of our planet,” said Professor Evi Nomikou, an expert in Geological Oceanography at the University of Athens. “We are simply observing these natural processes and moving away from sensationalist scenarios of destruction that only create panic.”

Scientists continue to monitor the situation closely, using a combination of methods to track the volcanic activity. For now, the next few weeks will be crucial in determining whether this volcanic unrest will lead to further developments, or whether the volcano will quiet down once again.