The source of one of the largest volcanic eruptions during the last 200 years had long remained a mystery, despite the fact it triggered multiple deadly famines and lowered worldwide temperatures. That was, until now. A team of scientists has just discovered the source of the highly explosive 1831 CE mystery eruption, at an understudied remote volcano. This video will discuss these findings, and what we still do not know about the volcano in question. Thumbnail Photo Credit: (Image color saturation increased, brightness increased in darker and shadowed areas of the image from the original image by) McGimsey, R. G., Alaska Volcano Observatory / U.S. Geological Survey, https://avo.alaska.edu/image/view/66321. This image was overlaid with text, and then overlaid with GeologyHub made graphics (the image border & the GeologyHub logo). Google Earth imagery used in this video: ©Google & Data Providers This video is protected under "fair use". If you see an image and/or video which is your own in this video, and/or think my discussion of a scientific paper (and/or discussion/mentioning of the data/information within a scientific paper) does not fall under the fair use doctrine, and wish for it to be censored or removed, contact me by email at geologyhubyt@gmail.com and I will make the necessary changes. Various licenses used in sections of this video (not the entire video, this video as a whole does not completely fall under one of these licenses) and/or in this video's thumbnail image (and this list does not include every license used in this video and/or thumbnail image): Public Domain: https://creativecommons.org/publicdomain/mark/1.0/ CC BY 3.0: https://creativecommons.org/licenses/by/4.0/legalcode CC BY 4.0: https://creativecommons.org/licenses/by/4.0/legalcode CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/legalcode Sources/Citations: [1] W. Hutchison, P. Sugden, A. Burke, P. Abbott, V.V.Ponomareva, O. Dirksen, M.V. Portnyagin, B.MacInnes, J. Bourgeois, B. Fitzhugh, M. Verkerk, T.J. Aubry, S.L. Engwell, A. Svensson, N.J.Chellman, J.R. McConnell, S. Davies, M. Sigl, G.Plunkett, The 1831 CE mystery eruption identified as Zavaritskii caldera, Simushir Island (Kurils), Proc. Natl. Acad. Sci. U.S.A. 122 (1) e2416699122, https://doi.org/10.1073/pnas.2416699122 (2025). CC BY 4.0. [2] Akulichev, V. & Astakhov, A. & Malakhov, M. & Aksentov, Kirill & Karabtsov, A. & Mar’yash, A. & Alatortcev, Alexander. (2016). The first discovery of cryptotephra of the catastrophic eruptions of the Baitoushan volcano in the tenth century A.D. in the shelf deposits of the Sea of Japan. Doklady Earth Sciences. 469. 887-891. 10.1134/S1028334X16080201. [3] Helama, S., Arppe, L., Uusitalo, J. et al. Volcanic dust veils from sixth century tree-ring isotopes linked to reduced irradiance, primary production and human health. Sci Rep 8, 1339 (2018). https://doi.org/10.1038/s41598-018-19760-w, CC BY 4.0. [4] Toohey, M. and Sigl, M.: Volcanic stratospheric sulfur injections and aerosol optical depth from 500 BCE to 1900 CE, Earth Syst. Sci. Data, 9, 809–831, https://doi.org/10.5194/essd-9-809-2017, 2017. CC BY 3.0. [5] ALL VEIs, dates/years, composition, tephra layer name, DRE estimates, and bulk tephra volume estimates for volcanic eruptions shown in this video which were assigned a VEI 4 or larger (and are not the 1831 eruption of the Zavaritsky Caldera) are sourced from the LaMEVE database (British Geological Survey © UKRI), https://www2.bgs.ac.uk/vogripa/view/controller.cfc?method=lameve, Used with Permission. [6] Source of Volcanic Explosivity Index (VEI) methodology and criteria: Newhall, C. G., and Self, S. (1982), The volcanic explosivity index (VEI) an estimate of explosive magnitude for historical volcanism, J. Geophys. Res., 87(C2), 1231–1238, doi:10.1029/JC087iC02p01231. Accessed / Read by Youtube.com/GeologyHub on Oct 5th, 2022. [7] van Dijk, E., Jungclaus, J., Lorenz, S., Timmreck, C., and Krüger, K.: Was there a volcanic-induced long-lasting cooling over the Northern Hemisphere in the mid-6th–7th century?, Clim. Past, 18, 1601–1623, https://doi.org/10.5194/cp-18-1601-2022, 2022., CC BY 4.0. This derivative image is also licensed under CC BY 4.0. [8] Sigl, M., Toohey, M., McConnell, J. R., Cole-Dai, J., and Severi, M.: Volcanic stratospheric sulfur injections and aerosol optical depth during the Holocene (past 11 500 years) from a bipolar ice-core array, Earth Syst. Sci. Data, 14, 3167–3196, https://doi.org/10.5194/essd-14-3167-2022, 2022. CC BY 4.0. [9] Wikipedia, "List of famines", https://en.wikipedia.org/wiki/List_of_famines, CC BY-SA 4.0 license [10] Wikipedia, "Tenpō famine", https://en.wikipedia.org/wiki/Tenp%C5%8D_famine, CC BY-SA 4.0 license [11] NOAA [12] Alaska Volcano Observatory 0:00 Mystery Eruption 1:58 Zavaritsky Caldera 2:41 1831 Eruption Size 3:53 Sulfur Dioxide 4:04 Blocking Sunlight 4:30 Middle Caldera