Supporting data of SWOT detects dispersive tsunami tied to a near-trench source in the 2025 Kamchatka earthquake

Tsunamis from large subduction earthquakes pose severe coastal hazards,
yet their genesis near the trench remains poorly constrained by land-based
seismic–geodetic data and distant deep water sensors. Following the 29
July 2025 magnitude 8.8 Kamchatka earthquake, the NASA/CNES Surface Water
and Ocean Topography (SWOT) satellite captured a distinct train of
short-wavelength tsunami waves, which we link to near-trench
tsunamigenesis. Sensitivity analyses of earthquake slip indicate
tsunamigenesis within ~10 kilometers of the trench — an inference not
attainable from land geodesy or sparse deep-water seafloor pressure
records alone. These results provide the first high-resolution,
two-dimensional spaceborne observation directly linking the measured
dispersive tsunami wavefield to near-trench tsunamigenesis, extending
earlier model- and gauge-based inferences. They establish SWOT as a
transformative constraint on source processes, with implications for
tsunami-hazard science and subduction-zone geodynamics.