Transoceanic propagation of the tsunami from 2025 Mw 8.8 Kamchatka Earthquake across the Pacific Ocean

The July 2025 Mw 8.8 Kamchatka earthquake triggered a transoceanic tsunami across the Pacific Ocean, with noticeable wave heights and coastal oscillations observed as far away as Chile. We compiled a comprehensive observational dataset consisting of 40 high-quality deep-ocean buoys and 10 coastal tide gauges distributed along the Pacific margins. We applied three fault slip models developed by the USGS and employed a dedicated framework to calculate the tsunami generation process in a multi-layered elastic Earth. A reliable source model was identified by comparing its output with tsunami observations. Detailed waveform, spectral, and energy-distribution analyses for deep-ocean and coastal tsunami data were conducted. Spectral analyses indicate that tsunami energy is concentrated within a broad source period band of 8–128 min, with stations normal to the fault strike dominated by 8–42 min periods and those aligned with the fault strike dominated by 42–128 min periods. This broad spectral content enabled resonance with coastal basins of varying spatial scales, producing prolonged oscillations at Pacific tide gauges, while local bathymetric shielding strongly attenuated tsunami energy even in the near field. Overall, transoceanic tsunami behavior reflects the combined influence of source geometry, directional energy radiation, and region-dependent coastal morphology, explaining the spatially heterogeneous and long-lasting impacts observed across the Pacific Ocean.