How large peak ground acceleration by large earthquakes could generate turbidity currents along the slope of northern Japan Trench

Progress in Earth and Planetary Science

Research Article

Ken Ikehara¹  Kazuko Usami²  Toshiya Kanamatsu³ 

[1] Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 7, 1-1-1 Higashi, 305-8567, Tsukuba, Ibaraki, Japan;Japan NUS Co. Ltd., Nishi-Shinjuku Prime Square 5F, 7-5-25 Nishi-Shinjuku, Shinjuku-Ku, 160-0023, Tokyo, Japan;Japan Organization for Metals and Energy Security (JOGMEC), 1-2-2, Hamada, Mihama-Ku, 261-0025, Chiba, Japan;Research Institute of Marine Geodynamics, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-Cho, 237-0046, Yokosuka, Kanagawa, Japan;

关键词: Paleoseismology;    Historical earthquake;    Peak ground acceleration;    Turbidite;    Japan Trench;   

DOI  :  10.1186/s40645-023-00540-8

 received in 2022-08-24, accepted in 2023-02-16,  发布年份 2023

来源: Springer

【 摘 要 】

Deep-sea turbidite has been used to determine the history of occurrence of large earthquakes. Surface-sediment remobilization is a mechanism of the generation of earthquake-induced turbidity currents. However, the detailed mechanism of surface-sediment remobilization caused by earthquake ground shaking is unclear. To understand how high peak ground acceleration (PGA) caused by a large earthquake can remobilize surface sediments, we determined the age of a surface-sediment core recovered from the mid-slope terrace (MST) of the inner slope of the Japan Trench in northern Sanriku to determine turbidites generated by large historical earthquakes and calculate the PGAs of these earthquakes using an empirical attenuation relation commonly used in Japan. Small offsets in radiocarbon ages and excess 210Pb activities between turbidite and hemipelagic muds suggest that the turbidites in the core resulted from surface-sediment remobilization. 137Cs and excess 210Pb chronologies indicate that the three uppermost turbidites in the core are correlated with three large historical earthquakes, namely the 1968 common era (CE) Tokachi-oki, the 1933 CE Showa–Sanriku, and the 1896 CE Meiji–Sanriku earthquakes. Calculation of PGAs for large historical earthquakes along the northern Japan Trench indicates that a PGA of > 0.6 g is necessary for turbidite deposition in the MST basin. This threshold is larger than that reported for central Sanriku and may vary spatially. Moreover, turbidites in the MST deposits are more frequent in the northern Japan Trench than in the central Japan Trench, suggesting that the occurrence of three types of large M8-class earthquakes in the northern Japan Trench might have contributed to the frequent occurrence of large PGAs.

【 授权许可】

CC BY   
© The Author(s) 2023

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