[M-IS11] 津波堆積物

[MIS11-P11] What cause sediment transport in Kuri-Kawashiri area, Ishikawa Prefecture, following the 2024 Noto earthquake?

*鄭 安棋¹、増田 英敏²、菅原 大助¹、サッパシー アナワット¹、今村 文彦¹ (1.東北大学災害科学国際研究所、2.東北大学理学研究科地学専攻)

キーワード：津波堆積物、土砂移動、2024能登地震、津波特徴、湾水振動、日本海東側

On 1 January 2024, a magnitude M7.5 earthquake occurred at a shallow depth of 15.5 km north of the Noto Peninsula, Japan. The tsunami was triggered following the strong motion of the earthquake. The tsunami propagates alongshore north Noto Peninsula and is diffracted into Iida Bay. In Iida Bay, it is seen that the tsunami wave is remarkably amplified due to repeated reflections and its irritation with incident waves. The large tsunami wave have triggered sediment dynamics in the Kuri-Kawashiri area, which does not apply to other regions in Iida Bay, suggesting a potential excitation source of bay oscillation, according to the site-specific feature, i.e., a long shallow bay. Given the background above, this study aim to explore the causes and to demonstrate the triggered mechanisms of tsunami sediment transport in Kuri-Kawashiri area through a hybrid approach. On one hand, the numerical tsunami simulation and sediment transport modeling are performed based on the validated earthquake fault model of Masuda et al., (2024) to examine the sediment dynamics, such as sediment transport, erosional and depositional mechanisms. On the other hand, the Fourier and Wavelet spectral analyses are applied to simulated coastal waveforms and the wavefields to characterize the tsunami wave features. Through the investigation, it is expected to clarify the factors responsible for the short-term coastal sediment transport in Kuri-Kawashiri area during the recent Noto tsunami event. The insights obtained from this study contributes to establishing a baseline information to tsunami-induced depositional process in Noto Peninsula from paleo-tsunami sources in east margin of Japan sea.