Volcano-tectonic evolution of the polygenetic Kolumbo submarine volcano/Santorini (Aegean Sea)

• Published in: Journal of volcanology and geothermal research 2015-01, Vol.291, p.101-111
• Main Authors: Hübscher, Christian, Ruhnau, M., Nomikou, P.
• Format: Article
• Language: English
• Subjects: Cones; Construction; Explosions; Explosive underwater volcanism; Extensional continental tectonics; Marine reflection seismics; Reflection; Seismic surveys; Tectonics and magmatism; Underwater; Volcanic activity; Volcanic hazards and risk; Volcanoes
• ISSN: 0377-0273; 1872-6097
• DOI: 10.1016/j.jvolgeores.2014.12.020

Here we show for the first time the 3D-structural evolution of an explosive submarine volcano by means of reflection seismic interpretation. Four to five vertically stacked circular and cone-shaped units consisting mainly of volcaniclastics build the Kolumbo underwater volcano which experienced its first eruption>70ka ago and its last explosive eruption 1650AD, 7km NE of Santorini volcano (southern Aegean Sea). The summed volume of volcaniclastics is estimated to range between 13–22km3. The entire Kolumbo volcanic complex has a height of≥1km and a diameter of≥11km. All volcaniclastic units reveal the same transparent reflection pattern strongly suggesting that explosive underwater volcanism was the prevalent process. Growth faults terminate upwards at the base of volcaniclastic units, thus representing a predictor to an eruption phase. Similarities in seismic reflection pattern between Kolumbo and near-by volcanic cones imply that the smaller cones evolved through explosive eruptions as well. Hence, the central Aegean Sea experienced several more explosive eruptions (≥23) than previously assumed, thus justifying further risk assessment. However, the eruption columns from the smaller volcanic cones did not reach the air and– consequently – no sub-aerial pyroclastic surge was created. The Anydros basin that hosts Kolumbo volcanic field opened incrementally NW to SE and parallel to the Pliny and Strabo trends during four major tectonic pulses prior to the onset of underwater volcanism. [Display omitted] •3D-architecture of an explosive submarine volcano shown for the first time by reflection seismic data interpretation.•Evidence for abundant explosive underwater volcanism in the southern Aegean Sea.•Hosting Anydros basin (southern Aegean Sea) opened incrementally north-west to south-east during four major pulses.•Volcanic cones adjacent to Kolumbo volcano evolved along an intra-basinal fault.