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

The 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. To investigate the transoceanic propagation of this event, we compiled a comprehensive observational dataset consisting of 41 high-quality DART (Deep-Ocean Assessment and Reporting of Tsunamis) buoys and eight representative coastal tide gauges distributed along the Pacific margins. We first applied three fault slip models released by the USGS and employed the PSGRN-PSCMP framework to simulate the tsunami generation process in a multi-layered elastic crust. The JAGURS tsunami package was employed for propagation modelling. The simulated waveforms were systematically validated against closest DARTs to the epicentre to identify the fault model that best reproduces the recorded tsunami (Figure 1). Detailed waveform, spectral, and energy-distribution analyses of both deep-ocean and coastal records were conducted to characterise the tsunami source properties and its transoceanic propagation patterns. Our results reveal pronounced tsunami directivity in both energy radiation and dominant wave periods. Tsunami energy propagates significantly more strongly along the fault-width direction than along the fault-length direction. Moreover, wave propagation parallel to the fault length is dominated by longer periods of 45–120 min, whereas energy components along the fault-width direction are concentrated at shorter periods of 8–45 min.