Santorini Caldera Rises Amid Persistent Earthquake Swarm

Geodynamic Institute Monitors Significant Seismic Shifts

The Santorini caldera has risen by up to 4 centimeters and moved 6 centimeters eastward since August 2024, according to Thanasis Ganas, research director at Greece's Geodynamic Institute. The shift, linked to ongoing seismic activity in the southeastern Aegean Sea, is being closely monitored as earthquakes continue to rattle Santorini and nearby islands, including Amorgos, which recently declared a state of emergency.

Unusual Ground Movement Raises Concerns

“We've observed vertical uplift of up to 4 cm and horizontal movement of about 6 cm to the east,” Ganas told Alpha TV. “Although this isn't necessarily alarming—we saw similar changes in 2011-2012 without an eruption—it’s a significant shift that requires ongoing observation.”

Persistent Earthquake Swarm

The seismic activity shows no signs of abating, with up to 140 earthquakes above 3.0 magnitude recorded daily. According to Kostas Papazachos, Professor of Seismology, this includes 15 to 20 quakes above 4.0 and one or two reaching magnitude 5.0 each day. “This pattern has persisted for about 12 days with no signs of diminishing,” Papazachos explained on Mega's “Live News” program.

The earthquakes occur in episodic clusters, often with gaps of 6 to 10 hours between them. Residents have noticed the pattern, humorously wishing the quakes would occur around 7-8 PM for a quieter evening.

Possible Causes: Fluid Movement, Not Magma

Papazachos emphasized that the quakes are likely caused by fluid movements within the Earth's crust rather than magma. “Magma and fluids are different things. Right now, there’s no evidence of magmatic material at depth, although it can’t be completely ruled out,” he noted.

Similar fluid-induced seismic activity has been observed in other tectonic areas, including the Sea of Marmara and Greece’s Ionian Islands, Kefalonia and Lefkada.

Monitoring and Preparedness

Authorities are closely monitoring the situation, particularly given the region's seismic history. The area is near an undersea fault line and lies within the Hellenic Volcanic Arc, known for its geological volatility.

While no major damage or volcanic activity has been reported, the ongoing caldera deformation and persistent quakes have heightened vigilance among scientists and local officials. The situation remains under continuous assessment as seismic activity shows no signs of slowing down.