Simple unilateral rupture of the great Mw 8.8 2025 Kamchatka earthquake.

On 29 July 2025, a moment magnitude (Mw) 8.8 great earthquake ruptured along offshore southern Kamchatka, with the aftershock region overlapping that of a 1952 Mw 8.8 to 9.0 event. Like 1952, the 2025 event nucleated at the northeastern end of the rupture, preceded by intense foreshock activity. Joint inversion of teleseismic and InSAR (Interferometric Synthetic Aperture Radar) data for the space-time slip distribution, with validation by means of forward modeling of deep-water tsunami recordings, revealed a southwestward elongated large-slip patch on the curved plate boundary. A slip of up to 14 meters was located offshore southern Kamchatka and Paramushir Island. The 1952 earthquake generated stronger tsunami signals in Hawaii, indicating a different slip distribution. Peak slip in 2025 exceeded the maximum slip deficit accumulated since 1952. Observations of volcanic eruptions after multiple great earthquakes in Kamchatka provide compelling evidence of earthquake-volcano interactions.