The volcanic material ejected from the Minoan eruption of the Santorini volcano was studied in depth by an international team of researchers, in order to discover the secrets of Europe’s largest volcanic eruption in the last 10,000 years, but also to contribute to the understanding of major volcanic eruptions worldwide.

The Department of Geology and Geoenvironment of the University of Athens (EKPA) also participates in the research.

Many of the most destructive volcanic eruptions in history have occurred on island volcanoes, so much of the material from the eruptions has been deposited on the sea floor. This makes it difficult to investigate this material to determine the true size of an explosion resulting in the size of these large events and the risks resulting from them are not yet well understood, even among experts.

An international group of scientists, led by the marine geoscientist, Jens Carstens of the German Center for Ocean Research GEOMAR Helmholtz in Kiel and with the participation of the associate professor of the Department of Geology and Geoenvironment of EKPA, Evie Nomiko, and researchers from institutions in Norway, the USA and France, accurately measured the Minoan eruption of the Santorini volcano, which occurred about 3,600 years, and the volcanic material that was ejected and deposited both on land and in the sea. Their study was published in the journal Nature Communications.

Combining the latest geophysical and geological methods, scientists have re-examined the Minoan eruption of Santorini and more precisely determined the volume of ejected magma, by which the size of an eruption is measured. As Evi Nomikos, associate professor of EKPA, explains to APE-MPE, through the study of this material “we are trying to piece together this “puzzle”, what the Santorini volcano looked like before the Minoan eruption, what it was like afterwards and how big was this tumor that erupted and spread around Santorini. We will only be able to discover this if we study the underwater space very well.”

The researchers in this new publication found that the volume of the material ejected on land and in the underwater area of ​​Santorini was 26-41 cubic kilometers, significantly smaller than previously assumed (estimates from previous calculations were 86 cubic kilometers of ejected magma). The volume of the ejected material gives information, moreover, about the volume of the magma chamber located below the volcano.

It is the first time that such precise values ​​have been calculated for all the individual components, as until now estimates of the eruption volume were based either on the estimation of the volume of the caldera collapse or on the incomplete record of the eruption products. Both approaches alone are limited in their explanatory power.

For the new calculations, the researchers combined different methods from several research missions.

For example, they were able to trace ash deposits from the Minoan eruption in 41 sediment cores collected during the Poseidon research mission in 2017 and thus determine the volume of the eruption’s ash. The data they collected even allowed them to characterize the material that fell into the center of the volcano’s crater.

“This publication is the result of the excellent cooperation between Greek and foreign scientists who participated in earlier oceanographic expeditions around the underwater area of ​​Santorini. Geological and geophysical data were collected and processed, and their combination led to the most correct interpretation of the volume of the Minoan eruption,” points out Ms. Nomikou.

With the new scientific approach, the research team drew conclusions about the true extent of the Minoan eruption and ultimately created a more reliable reference point for better classification and measurement of other large volcanic eruptions worldwide.

“Eruptions can cost lives and even affect the climate. We are pleased to have contributed with our research to a step towards a better understanding of these large-scale events and, consequently, to the improvement of risk assessment”, explains team leader Dr. Jens Carstens.

Research now continues with subsea research drilling in December 2022 and January 2023 as part of the International Ocean Exploration Program (IODP) major oceanographic mission. The underwater drilling was carried out in the points indicated by the research team as critical, after the analysis of the seismic profiles and the topography of the underwater floor, so that the volume of the volcanic material of the Minoan eruption of Santorini could also be confirmed with the drilling.