2024 Volume 80 Issue 17 Article ID: 24-17002
Tsunamis are generated by diverse mechanisms associated with seafloor deformations. The 2024 Noto earthquake highlighted the significance of seafloor slope failures and coastal sea-level uplifts. Conventional tsunami numerical models estimate seafloor vertical displacement distributions using fault models, set them as initial sea surface displacements, and release them instantaneously to simulate wave propagation. While this approach satisfies the water mass conservation condition, it neglects horizontal water movement. This study re-derives tsunami equations incorporating the time derivative term of seafloor displacement arising from the vertical integration of the mass conservation equation. We compare initial wave shapes and propagation results for various seafloor deformations with those of conventional models. Quantitatively, tsunami arrival times differ by about 30 seconds for a propagation distance of 40 km in 100 m uniform water depth.
