The July 29, 2025 Kamchatka Earthquake, MW 8.9: Examination Based on Regional Data Through End-2025

This article presents data on the MW 8.9 Kamchatka earthquake of July 29, 2025, compiled by the Kamchatka Branch of the Geophysical Survey of the Russian Academy of Sciences (KB GS RAS) as of December 31, 2025. The Kamchatka earthquake is one of the largest seismic events in the history of instrumental observations. To date it ranks as the sixth most powerful event ever recorded in the world. The rupture zone, estimated based on the aftershock area, is 580 × 180 km and roughly coincides with the source area of the Great Kamchatka Earthquake of November 4, 1952 (MW 9.0). The 73-year gap between these two megathrust earthquakes that occurred approximately in the same area is significantly shorter than what would be expected from the widely accepted concepts of the seismic cycle. The article provides information on source parameters of the main shock, the operation of the Tsunami Warning Service, a catalog of aftershock mechanisms, the characteristics of strong ground motions caused by the main shock, and a brief description of the manifestation of a tsunami. A preliminary assessment of the macroseismic impact of the Kamchatka earthquake and its aftershocks revealed that the earthquake caused shaking of intensity 7–8 on the SIS-17 scale in Severo-Kurilsk and 6–7 in Petropavlovsk-Kamchatsky; no human casualties or serious damage caused by the earthquake and tsunami were recorded throughout the entire area of their propagation. Features of the source process development revealed by the results of the analysis of the diurnal variation of seismic energy released after the main event are discussed. The finite fault slip model of the earthquake based on the coseismic displacements from GNSS observations is presented.