Santorini in danger (again)?

It has been quiet for nearly 400 years, but Kolumbo (κόλυμβη means 'diver'), an underwater volcano just off the Greek island of Santorini, is not asleep. In fact, Kolumbo is a sleeping menace.

[Kolumbo lies northeast of Santorini]

 

The last time Kolumbo erupted, in 1650, it killed 70 people, but population growth and tourism on Santorini could mean the impact of an unexpected equivalent eruption today could be far greater.

A previously undetected magma chamber is gradually filling with melt (molten rock), prompting researchers to recommend real-time monitoring of the volcano[1]. The melt reservoir extends from about two to at least four kilometers below sea level. The chamber coincides with the termination point of the recent earthquake swarms and may be a missing link between a deeper melt reservoir and the high-temperature hydrothermal system venting at the crater floor[2].

[Kolumbo, an underwater volcano]

 

Kolumbo belongs to the highly explosive family of volcanoes, capable of producing an eruption column tens of kilometres high. It is also liable to trigger a tsunami, making it a highly dangerous prospect. Using a new imaging technique, rather similar to a medical ultrasound, Kajetan Chrapkiewicz, and his colleagues spotted melt gathering roughly two miles beneath the volcano[3]. Their conclusions suggest that, although an eruption is not imminent, the volcano does pose a serious threat.

While Kolumbo is situated just 15 kilometers to the northeast of the center of Santorini caldera, the magmatic systems of Kolumbo and Santorini are unrelated and Kolumbo taps a distinct enriched mantle source[4].

The last eruption of Santorini was between 1600 and 1525 BC. That eruption buried the Minoan settlement on the island in a layer of ash and pumice more than 40 meters deep. The effects of the eruption were felt as far away as Egypt and it heralded the end of the Minoan civilisation. It is now understood that this eruption was the basis of the myth of Atlantis.

[1] Chrapkiewicz et al: Magma Chamber Detected Beneath an Arc Volcano With Full-Waveform Inversion of Active-Source Seismic Data in Geochemistry, Geophysics, Geosystems – 2022. See here.
[2] Schmid et al: Heralds of Future Volcanism: Swarms of Microseismicity Beneath the Submarine Kolumbo Volcano Indicate Opening of Near-Vertical Fractures Exploited by Ascending Melts in Geochemistry, Geophysics, Geosystems – 2022. See here.
[3] Paulatto et al: Advances in seismic imaging of magma and crystal mush in Frontiers in Earth Science - 2022. See here.
[4] Klaver et al: A distinct source and differentiation history for Kolumbo submarine volcano, Santorini volcanic field, Aegean arc in Geochemistry, Geophysics, Geosystems – 2016. See here.