GEOMAR researchers have utilized 3D seismics to reconstruct the historic eruption of the Kolumbo underwater volcano in the Aegean Sea in 1650. The eruption triggered a devastating tsunami that was witnessed and recorded by historical accounts. The study, led by Dr. Jens Karstens from the GEOMAR Helmholtz Centre for Ocean Research Kiel, sheds light on the sequence of events leading to the natural disaster.
Eyewitnesses reported that the water around the Greek island of Santorini had changed color and was boiling in the weeks leading up to the eruption. Glowing rocks were ejected from an underwater volcano that had risen from the sea, accompanied by fire, lightning, and plumes of smoke. Moments later, the water receded before surging toward the coastline with waves reaching up to 20 meters high. The explosion generated a loud bang, pumice and ash fell on surrounding islands, and a cloud of poisonous gas claimed several lives.
Dr. Karstens explains that the details of the historic eruption were documented by a French volcanologist in the 19th century. However, the researchers sought to understand the mechanics behind the tsunami and the violent volcanic explosion. Their investigation involved studying the underwater crater of Kolumbo using advanced imaging technology.
On the decommissioned research vessel POSEIDON, the team employed 3D seismic methods to create a three-dimensional image of the crater, revealing its dimensions of 2.5 kilometers in diameter and 500 meters in depth. The imaging also showed that one flank of the cone had experienced severe deformation. Based on these findings, the researchers compared the possible mechanisms that led to the tsunami with the historical eyewitness accounts. They concluded that a combination of a landslide followed by a volcanic explosion was responsible for the catastrophic event.
By integrating 3D seismics with computer simulations, the team reconstructed the height of the waves generated by the explosion alone. However, the simulated data did not match the eyewitness observations. Only when the landslide was considered in the simulations did the results align with historical records. The researchers propose that the unstable pumice slopes of Kolumbo, combined with the continuous ejection of lava during the eruption, led to immense pressure buildup. The collapse of the flank resulted in a sudden release of pressure and a massive explosion.
The study provides valuable insights for monitoring programs aimed at active submarine volcanic activity. The researchers hope that their findings can contribute to the development of new approaches, and potentially an early warning system, for detecting volcanic unrest in real-time. The team’s ultimate goal is to improve our ability to mitigate the impacts of future volcanic eruptions and tsunamis.
The research was published in the journal Nature Communications on October 26, 2023. The study was co-authored by Dr. Gareth Crutchley and involved collaboration between German and Greek scientists. The National and Kapodistrian University of Athens (NKUA) is leading the SANTORY program, which aims to monitor volcanic activity in the Santorini region.