Scenario of the 1996 volcanic tsunamis in Karymskoye Lake, Kamchatka, inferred from X-ray tomography of heavy minerals in tsunami deposits

• Published in: Marine Geology
• Main Authors: Falvard, Simon, Paris, Raphael, Belousov, Marina, Belousov, Alexander, Giachetti, Thomas, Cuven, Stéphanie
• Other Authors: Laboratoire Magmas et Volcans (LMV), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Centre National de la Recherche Scientifique (CNRS), Earth Observatory of Singapore (EOS), Nanyang Technological University Singapour, Laboratoire de Géographie Physique et Environnementale (GEOLAB), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: Tsunami; Phreato-magmatic eruption; Heavy minerals; X-ray tomography; Karymskoye; Lake; [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology; Kamchatka
• Online Access: https://uca.hal.science/hal-01738081; https://doi.org/10.1016/j.margeo.2017.04.011

co-auteur étranger International audience The concentration and distribution of heavy minerals in tsunami deposits is not random and mostly sourcedependent.Heavy minerals may thus be good indicators of sediment provenance and tsunami flow dynamics.The tsunamis generated by the 1996 phreato-magmatic eruption in Karymskoye Lake represent a relevant casestudybecause the provenance of the abundant heavy minerals found in the tsunami deposits is well constrained(the on-going basaltic eruption itself). X-ray computed tomography (X-CT) of cores of tsunami sediments is usedto identify heavy minerals and characterise their source and spatial distribution in the tsunami deposit, and topropose a scenario of the coupled eruption and tsunamis. An original combination of methods including X-CT,SEM and XRF core scanner allows distinguishing subunits corresponding to pulses of sediments deposition andassociated inputs of heavy minerals, together with erosive contacts, laminations, and rip-up clasts of thesubstratum. The structure of the tsunami deposits suggests that a major tsunami consisting of two main wavesinundated the coastal terrace up to 100 m inland on the eastern shore of the lake; a scenario that is consistentwith waves generated by experimental explosions. This largest tsunami might have occurred when underwaterexplosions were at a critical water depth of 40 m (corresponding to a two-third submerged explosion in the 60 mdeep lake). However, more investigations are needed to better understand the critical conditions leading to atsunami during underwater eruptions.