[M-IS23] New frontiers in geology

[MIS23-06] Reworked whale-bones by the Tsunami triggered by Noto Peninsula Earthquake on Jan. !st, 2024: Research shift from whale-fall coomunities to vertebrate taphonomy

★Invited Papers

*Robert Jenkins¹, Shozo Ogiso², Yoichiro Kitani², Haruka Fukaki³, Yohei Hashizaki³, Mayu Yamamoto³, Yuma Miyake³, Kosuke Matsubara⁴, Nobuo Suzuki² (1.School of Geosciences and Civil Engineering, College of Science and Engineering, Kanazawa University, 2.Noto Marine Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, 3.Division of Geosciences and Civil Engineering, Graduate School of Natural Science and Technology, Kanazawa University, 4.Faculty of Health Science, Institute of Medical, Kanazawa University)

Keywords:Tsunami, Redposition, fossilization process, Taphonomy

The Tsunami evoked by the Noto Peninsula Earthquake happened on January 1^st of 2024 hit the Tsukumo Bay where we have deployed whale-carcasses to know decaying processes of whale bones and formation processes of whale-fall communities in shallow waters. We set several set of whale carcasses on muddy bottom at around 12 to 16 m deep during 2020-2023.
Three weeks after the earthquake and the tsunami, we conducted scuba dives to search for carcasses. Sea floor from depth of 10 to 20 m has been changed drastically due to the tsunami. There are many lines of large dunes composed of conglomerates, including boulders size, and mud. During the scuba diving, we found some bones which we deployed at a depth of 18 to 20 m. One skull buried more than half in muddy sediment. One day before the scuba diving, we took ca. 20 cm long sedimentary core by using multiple corers at 22 m deep in the Tsukumo Bay. The core contains ca. 8 cm of event deposit which we considered. The deposits is composed of thin sandstone layers and covering thick mud layer on top. Those observations obviously indicated that the whale-carcasses were reworked and buried by the Tsunami happen on January 1^st of 2024.
We will continue to research on the carcasses to understand what happened in shallow marine environment by the Tsunami and reveal this rare example of fossilization process of vertebrate bones.