Submarine landslide induced tsunami modeling using 3D slope stability analysis Method: The 2024 Noto Peninsula earthquake and tsunami in Toyama Bay, Japan

A 7.5 M_w earthquake and tsunami occurred along the coast of the Noto Peninsula in January 2024, with the tsunami expected to reach Toyama Bay 20 min after the earthquake. However, waveform data showed that waves arrived within 3 min, these unexpected waves suggest the involvement of a submarine landslide. This study aims to model the tsunami generated by submarine landslides, excluding any earthquake contribution. Hovland's three-dimensional slope stability analysis for cohesive-frictional soils was applied to estimate the landslide mass and location. The estimated landslides were then used as sources for tsunami generation in the TUNAMI-N2 two-layer model, which is based on the shallow water equations. The tsunami waveform was then validated against observed data from the wave and tide gauges. The model produced submarine landslides with estimated masses ranging from 0.015 to 1.28 km². These results confirm the submarine landslides in this region and the simulated waveforms closely matched the observed data, confirming the arrival of tsunami within 3 min. Although this model could not fully reproduce all features of the observed waveform, the findings provide strong evidence that submarine landslides played a crucial role in the early tsunami arrival and highlight their importance of future tsunami hazard assessment.