Revising the volume of the Minoan eruption (Santorini) based on new marine geophysical and sedimentological data.

Karstens, Jens , Schmid, Florian , Elger, Judith , Berndt, Christian , Crutchley, Gareth J. , Kutterolf, Steffen , Kühn, Michel , Preine, J., Van der Bilt, W., Hooft, E., Druitt, T.H., Cederstroem, J.M., Hübscher, C., Nomikou, P. and Carey, S. (2022) Revising the volume of the Minoan eruption (Santorini) based on new marine geophysical and sedimentological data. Open Access [Talk] In: 11. Conference Cities on Volcanoes (COV11). , 12.06.2022-17.06.2022, Heraklion, Greece .

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With a maximum volume estimate of up to 86 km³ dense-rock equivalent (DRE), the Minoan
Eruption is considered one of the largest Holocene eruptions. However, as most eruption
products were deposited in the Mediterranean, previous volume estimates based on a limited
database. We present new marine geophysical and sedimentological datasets allowing us to
reassess the volume of the Minoan eruption in unprecedented detail. We combine high-
resolution reflection seismic and P-wave tomography datasets with more than 40 marine
sediment cores, constrained by X-ray computer-tomography (CT) scanning. The reflection
seismic profiles indicate an ignimbrite volume of ~5.7 km³ DRE deposited on Santorini’s
flanks, which is seven times smaller than previous estimates, while the P-wave tomography
indicates ~5.5 km³ DRE of Minoan intra-caldera deposits, which is four times smaller than
previous estimates. CT-guided analysis of the sediment cores allows us to differentiate two
ash layers, which are separately integrated into ash deposit isopach maps and allows
determine deposit porosities with high accurary. The combined ash volume of ~19.5 km³
DRE is in the same order as previous estimates. This yields a total eruption volume of ~31
km³ DRE. In addition, we use the new datasets to constrain the post-eruptive topography of
the caldera and estimate the caldera collapse volume to be ~31.5 km³. The internal
consistency of both independent approaches implies high confidence in our estimates, likely
representing the most precise volume reconstruction of any major (M6.5+) volcanic eruption
in the Holocene. Our analysis implies that the Minoan Eruption was smaller and produced
significantly less ignimbrites than previous reconstructions indicated, while still causing a
devastating tsunami. This highlights the significant tsunamigenic potential of submarine-
emplaced ignimbrites

Document Type: Conference or Workshop Item (Talk)
Keywords: Minoan eruption
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
Date Deposited: 08 Jan 2024 07:25
Last Modified: 08 Jan 2024 07:26

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