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Cape Riva versus Minoan eruption: reassessing the magnitude of caldera-forming eruptions at Santorini

María Blanch Jover1, Jens Karstens1, Steffen Kutterolf1, Willem Godert Maria van der Bilt2, Aaron Arneke3, Heidrun Kopp1, Christian Berndt1, Gareth J. Crutchley1, Jonas Preine4, Paraskevi Nomikou5

  • Affiliations: 1GEOMAR Helmholtz Center for Ocean Research Kiel, Kiel, Germany 2Department of Earth Science and Bjerknes Centre for Climate Research, University of Bergen, Bergen, Norway 3University of Tübingen, Tübingen, Germany 4Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, USA 5Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, Athens, Greece 

  • Presentation type: Poster

  • Presentation time: Thursday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 161

  • Programme No: 2.2.25

  • Theme 2 > Session 2

Abstract

Although caldera-forming eruptions are among the most catastrophic natural hazards, an accurate quantification of the volume of ejected material and their magnitude remains a challenge. Santorini in the Aegean Sea is one of the world's most prominent calderas and the result of at least five caldera-forming eruptions. The 1600 BCE Minoan eruption represents the most recent caldera-forming event, and is among the most extensively studied eruptions worldwide. While recent marine geological and geophysical analyses enabled reconstruction of its volume and temporal evolution in greater detail, little is known about its predecessor, the caldera-forming Cape Riva eruption, which occurred ~22 ka. New analyses of marine sediment cores suggest that the Cape Riva eruption produced a tephra volume comparable to or exceeding that of the Minoan eruption.  Here, for the first time, we integrate high-resolution 2D and 3D seismic reflection data with sedimentological constraints from marine sediment cores to assess the volume of the Cape Riva eruption with high precision, and compare it to the Minoan eruption. Our results indicate that the Cape Riva eruption deposited, at least locally, a significantly thicker offshore ignimbrite layer than did the Minoan eruption. This suggests that the volume of the Cape Riva eruption might have exceeded that of the Minoan eruption, and that previous estimates of the offshore ignimbrite for the Minoan eruption might have been overestimated. Our study highlights the complexity of evaluating large-scale eruption products in the marine environment, and underscores the importance of integrating high-resolution seismic imaging with marine sedimentological analyses.