Modeling the 2024 Noto Peninsula earthquake tsunami: implications for tsunami sources in the eastern margin of the Japan Sea

Abstract

A moment magnitude (Mw) 7.5 earthquake occurred on January 1, 2024, at the northern tip of the Noto Peninsula, Central Japan, triggering a large tsunami. Seismological and geodetic observations revealed the rupture of mapped submarine active faults. While proximal segment ruptures were well resolved by existing researches, distal segments posed challenges for onshore tsunami observations, prompting the need for a comprehensive study on wave sources. We aimed to examine tsunami propagation and inundation using three different fault models to identify the general characteristics of the tsunami source and evaluate the complexities of earthquake and submarine landslide-induced tsunamis. The study identified the simultaneous rupture of two active fault systems as the most suitable model for explaining observed tsunami height and inundation; however, some inconsistencies with observations remain. The propagation process did not follow a concentric pattern but aligned with bathymetric heterogeneity. The findings also suggested potential amplification effects responsible for Iida Bay’s coast devastation and indicated a possible submarine landslide in southern Toyama Bay. The findings of the present work will benefit the exploration of a more realistic tsunami source model, considering the differences between observations and simulations. Such efforts, in collaboration with paleotsunami research, will contribute to the improved assessment of hazards from submarine active faults.