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The Kolumbo eruption in the Aegean Sea in 1650 was caused by a landslide and resulted in a tsunami.


A seismic profile line through Kolumbo volcano, showing the volcanic cone, the landslide deposit and the shear plane. Image from Karstens et al. (2023).

Dave Petley, a renowned expert in the field of landslide research and management, is the author of The Landslide Blog.

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In the year 1650, a powerful tsunami hit the Aegean Sea, a body of water between Greece and Turkey. There is an informative online presentation detailing the tsunami and its impact. Records show that the tsunami caused destruction to crops, ships, vegetation, and religious buildings on Santorini Island. Archaeological and geological findings provide solid proof of this event.

The cause of the tsunami has been identified as an underwater volcano named Kolumbo, situated approximately 7 km northeast of Santorini. The volcano had been active for a few weeks before the tsunami occurred. On September 29, 1650, a massive explosion was heard up to 100 km away from Santorini as the volcano erupted in a catastrophic manner. The resulting tsunami waves reached heights of up to 20 m and affected islands in the southern Aegean Sea and the northern coast of Crete.

There has been much speculation about the possible cause of the devastating eruption, with some suggesting that a collapse of the volcanic cone due to a submarine landslide may have been the trigger. Recently, a team of researchers conducted a study on this hypothesis and their findings have been published in the open access journal Nature Communications (Karstens et al. 2023). Using 3D seismics, the team mapped the area of Kolumbo, creating detailed profiles of the crater and the seabed around it.

The paper presents a perspective view of the bathymetry data, which reveals the crater, landslide deposit, and clear detachment surface – also known as the shear surface in landslide terminology.

3D bathymetry data for Kolumbo volcano, showing the volcanic cone, the landslide deposit and the shear plane.

The image from Karstens et al. (2023) displays 3D bathymetry data of Kolumbo volcano, depicting the volcanic cone, the landslide deposit, and the shear plane.

The seismic profile of the presumed landslide deposit clearly shows that it was a collapse of the side.

A seismic profile line through Kolumbo volcano, showing the volcanic cone, the landslide deposit and the shear plane.

The image from Karstens et al. (2023) displays a seismic profile of Kolumbo volcano, highlighting the volcanic cone, landslide deposit, and shear plane.

During the eruption, the sides of the volcano became unstable and experienced a significant landslide, estimated to be 1.2 cubic kilometres in volume. This caused the cap of the magma chamber to be removed, revealing a large amount of pressurized gas. The resulting explosion was massive and formed the visible crater, measuring 2.5 km in diameter and 500 m deep as seen in the images.

The researchers have simulated the potential tsunami caused by a series of events, including a collapse of the flank followed by an eruption triggered by explosives. They then compared this scenario to the simulation of a tsunami solely caused by an explosion. The results showed that the first sequence more closely matches the observed tsunami.

Over the past few weeks, we have observed a significant GLOF (glacial lake outburst flood) caused by unstable slopes, as well as evidence of a volcanic eruption and resulting tsunami caused by a landslide. I have always believed that slope instability is not given enough recognition as a major trigger for various types of hazards.

Reference

The authors of this article are Jens Karstens, Gareth J. Crutchley, Thor H. Hansteen, Jonas Preine, Steven Carey, Judith Elger, Michel Kühn, Paraskevi Nomikou, Florian Schmid, Giacomo Dalla Valle, Karim Kelfoun, and Christian Berndt. The article discusses the series of events that occurred during the 1650 volcanic eruption of Kolumbo and their potential to cause tsunamis. It was published in Nature Communications with a DOI of 10.1038/s41467-023-42261-y.

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