Overview
- A magnitude 8.8 earthquake on July 29, 2025 in the Kuril‑Kamchatka subduction zone generated a trans‑Pacific tsunami captured in detail by NASA–CNES’s SWOT satellite.
- The satellite recorded a roughly 120‑kilometer‑wide swath of the sea surface, providing the first high‑resolution, space‑based track of a major subduction‑zone tsunami.
- SWOT observations showed complex, interacting waves that contradicted the long‑held assumption that large tsunamis behave as non‑dispersive single waves.
- Models that included dispersion reproduced the satellite measurements more accurately, and inconsistencies in DART arrival times exposed gaps in earlier simulations.
- An inversion that combined SWOT data with DART buoy records indicated the earthquake rupture extended about 400 kilometers, longer than prior ~300‑kilometer estimates and pointing to the value of integrating satellite swaths into future forecasting workflows.