During October 2023, three small magnitude tsunamis struck Japan which did not originate from a large magnitude earthquake. While initial evidence pointed towards a possible underwater volcanic eruption, the truth is a bit more complex. A landslide, a lengthy magma intrusion, earthquakes, a caldera collapse, and an underwater volcanic eruption were all to blame. Note: This video's stock image is not of one of the 2023 tsunamis in question, and is just a stock image of a high wave off of Bali in Indonesia. If you would like to support this channel, consider using one of the following links: (Patreon: http://patreon.com/geologyhub) (YouTube membership: https://www.youtube.com/channel/UCYeGh5VML5XPr5jYnzh3J6g/join) (Gemstone & Mineral Etsy store: http://prospectingarizona.etsy.com) (GeologyHub Merch Etsy store: http://geologyhub.etsy.com) 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 [email protected] 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 4.0: https://creativecommons.org/licenses/by/4.0/legalcode Sources/Citations: [1] Obana, K., Ito, A., Fujiwara, T. et al. Earthquake activity in the Torishima Rift and Sofu Seamount, and its relationship to the October 2023 tsunamis in Japan. Earth Planets Space 77, 56 (2025). https://doi.org/10.1186/s40623-025-02185-x, CC BY 4.0. Note: this source was also used to guesstimate where the implied magma dike was during October 2023. [2] Fujiwara, T., Imai, K., Obayashi, M., Yoshida, K., Tada, N., Obana, K., et al. (2024). The Sofu Seamount submarine volcano present in the source area of the October 2023 earthquakes and tsunamis in Japan. Geophysical Research Letters, 51, e2024GL109766. https://doi.org/10.1029/2024GL109766, CC BY 4.0. This paper was used to approximate where the new caldera formed and where the submarine landslide occurred. [3] Hiroki Minami, Kenichiro Tani, Morphological evidence of an explosive eruption event in October 2023 at Sofu Seamount in the Izu-Bonin Arc, Marine Geology, Volume 477, 2024, 107405, ISSN 0025-3227, https://doi.org/10.1016/j.margeo.2024.107405. (https://www.sciencedirect.com/science/article/pii/S0025322724001890) [4] M. Yamada, M. Nakano, Seismic source mechanism of the tsunami near the Sofu Seamount on October 8, 2023, Journal of Volcanology and Geothermal Research, Volume 464, 2025, 108354, ISSN 0377-0273, https://doi.org/10.1016/j.jvolgeores.2025.108354. (https://www.sciencedirect.com/science/article/pii/S0377027325000903) [5] Sandanbata, O., Watada, S., Satake, K., Kanamori, H., & Rivera, L. (2023). Two volcanic tsunami events caused by trapdoor faulting at a submerged caldera near Curtis and Cheeseman Islands in the Kermadec Arc. Geophysical Research Letters, 50, e2022GL101086. https://doi.org/10.1029/2022GL101086, CC BY 4.0. 0:00 Mystery Tsunamis 0:34 M6 Earthquakes 1:18 CLVD Earthquakes 1:36 Earthquake Swarm 2:30 Submarine Landslide