International team of researchers accurately measures size of ancient Greek volcanic eruption

Volcanic eruptions can have severe global impacts, but accurately measuring the size of such eruptions can be challenging. To classify the size of volcanic eruptions, volcanologists estimate the magma volume and deposition volume. However, it is often difficult to determine these values accurately, making it challenging to infer the actual volume of magma and measure the complete extent of such eruptions.

Research Findings

An international team of researchers led by marine geoscientist Dr. Jens Karstens of GEOMAR Helmholtz Center for Ocean Research Kiel has now, for the first time, combined the latest geophysical and geological methods to resurvey the Minoan eruption, which took place 3,600 years ago, of the Greek island of Santorini. Their study has now been published in the journal Nature Communications.

The researchers were able to accurately measure the volume of the Minoan eruption, which was previously estimated to be as large as 86 cubic kilometers of ejected magma. The science team’s new analysis yields much smaller numbers: Only one-third to one-half as large, 26–41 cubic kilometers, was the event at the time, according to current estimates. The publication provides a basis for better assessing the hazard of such events and establishes a benchmark for more precisely determining magma volumes.

Importance of Research

Volcanic eruptions can result in measurable effects worldwide, such as a global temperature decrease. While we have a relatively good understanding of the risk from earthquakes, we are much worse off when it comes to volcanoes. It is therefore essential that we learn to assess the consequences of large explosive volcanic eruptions more accurately. To better assess the risk, it is necessary to know how frequently eruptions of a certain size occur. The basis for this is volume calculations that are as precise as possible. The research conducted by Dr. Jens Karstens and his team of researchers contributes to this understanding and provides a benchmark for future research.

The Minoans were the earliest advanced civilization in Europe, and the eruption named after them took place about 3,600 years ago in the Holocene epoch, burying an entire city. The eruption has been studied for years, but the new analysis yields much smaller numbers than previously estimated. For their calculations of the volcanic magnitude, the researchers combined different methods from several research cruises, including detecting ash deposits from the Minoan eruption in sediment cores collected during research cruise POS513 aboard the research vessel POSEIDON in 2017, and using a computed tomography-based technique to determine the density of the sediment cores and thus the actual pure magma volume ejected.

Combining the data collected, the scientists were able to draw conclusions about the extent of the Minoan eruption. This is the first time that such precise values have been calculated for all individual components. The publication establishes a benchmark for more precisely determining magma volumes, which is essential for assessing the consequences of large explosive volcanic eruptions more accurately.