Preliminary modeling and analysis of the Tsunami generated by the 2024 Noto Peninsula earthquake on 1 January: Wave characteristics in the Sea of Japan

In this study, the January 1, 2024, earthquake and tsunami that struck the Noto Peninsula in Ishikawa Prefecture, Japan, with a magnitude of 7.6 was investigated. This study provides a comprehensive analysis of the geological context, faulting mechanisms, and tsunami propagation of this event to gain insights into the complex dynamics of tsunami generation and amplification. The research involves simulation models based on two fault scenarios provided by the Geospatial Information Authority of Japan (GSI) and the United States Geological Survey (USGS), coupled with Fourier spectral and modal analyses. Here, the spatial distribution, waveform characteristics, and resonance effects of tsunami waves across the Sea of Japan are examined. The tsunami impacted various locations in South Korea and Russia, striking the west coast of the Sea of Japan. The most severe damage occurred in the town of Suzu, Japan, with a tsunami height of 4.7 m. The highest recorded tsunami wave reached a height of 6.6 m, approximately 100 km from the earthquake epicenter. South Korea's highest recorded tsunami height was approximately 0.9 m at Mukho. The highest recorded height in Russia was approximately 0.4 m at Rundnaya. Overall, comparisons between simulated and recorded tsunami waveforms at various tide gauge stations in Japan, South Korea, and Russia yielded suitable results. However, large discrepancies were seen at some tide gauge stations which can be attributed to the low resolution of topographic data. The Root-Mean-Square-Error analysis of the waveform highlights that the USGS scenario (finite fault) was slightly more accurate in terms of spatial distribution than that of the GSI scenario (uniform fault). In contrast, the GSI scenario was more accurate in terms of simulating tsunami height than the USGS scenario. The spectral density of this event was computed via spectral analysis, revealing five dominant period modes: 120, 72, 42.4, 26.7, and 20.6 min for the GSI and 120, 55.4, 40, 30, and 27.7 min for the USGS. Modal analysis was used to investigate the eigenmodes of natural oscillations. It found that periods of the 1st to 3rd modes are 761, 424, and 385 min, respectively. A comparison between the dominant mode and eigenmode of modal analysis reveals that the increase in amplification might not be impacted by the natural oscillation mode in the Sea of Japan due to the 2024 Noto Peninsula tsunami event.