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Volcano-Tectonic Coupling at the Christiana-Santorini-Kolumbo Volcanic Arc

Jonas Preine1,2, Christian Hübscher1, Emilie Hooft3, Abigail Metcalfe4, Tim H. Druitt4, Beck Hufstetler4, Kaisa Autumn4, Gareth Crutchley5, Jens Karstens5, Masako Tominaga2, Adam Woodhouse7,8, Olga Koukousioura9, Shun Chiyonobu10, Steffen Kutterolf5, Paraskevi Nomikou6, Thomas Ronge7

  • Affiliations: 1Institute of Geophysics, University of Hamburg, Bundesstrasse 55, D-20146 Hamburg, Germany 2Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole MA 02543, USA 3Laboratoire Magmas et Volcans, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France 4Department of Earth Sciences, University of Oregon, 125C Cascade Hall, 1272 University of Oregon, Eugene, OR 97403-1205, USA 5GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, D-24148 Kiel, Germany 6Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, 15784 Athens, Greece 7Institute for Geophysics, University of Texas, J.J. Pickle Research Campus, Bldg. 196, Austin TX 78758, USA 8School of Earth Sciences, University of Bristol, BS8 1RJ, Bristol, UK 9School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 10Faculty of International Resource Sciences, Akita University, Akita, Akita Prefecture 0108502, Japan

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 17

  • Programme No: 1.5.24

  • Theme 1 > Session 5

Abstract

11Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan *12International Ocean Discovery Program, Texas A&M University, College Station TX 77845, USA * Silicic volcanic systems are observed globally in areas of local extensional or transtensional stress, especially in continental rift zones and back-arc regions. However, the role of crustal faults in magma migration remains poorly understood. The Christiana-Santorini-Kolumbo volcanic field, located in the South Aegean Volcanic Arc, offers the opportunity to investigate the interplay between volcanism and tectonism in a continental rift zone. Integrating high-resolution seismic reflection data with deep-earth sampling from IODP Expedition 398, we unravel a coupling mechanism between crustal faulting and explosive volcanism in this region. Our findings reveal a major NE-SW-striking normal fault parallel to the Kolumbo Volcanic Chain (KVC), defining a tectonic half-graben structure. This fault, previously considered to exhibit limited vertical offset, shows a displacement exceeding 200 m based on tephra and biostratigraphic markers recovered from cores. The volcanic edifices of the KVC are situated approximately 6 km from the surface trace of this fault on its hanging wall. Adjacent non-volcanic rift basins display pervasive internal faulting at comparable distances from basin-bounding faults, implying that these zones of localized extension provide preferential pathways for magma ascent. P-wave tomography data suggest that the tectonic graben system hosting the KVC may extend beneath Santorini, explaining the linear orientation of volcanic features at Santorini and the KVC. We show that the listric Kolumbo Fault may intersect Kolumbo Volcano's mid-crustal magma reservoir, facilitating melt migration through fault-induced shearing. Our study implies a critical influence of normal faulting on magma migration and emplacement in extensional back-arc systems.