Long-Term Earthquake Prediction by S. A. Fedotov for the Kuril–Kamchatka Arc and the Kamchatka Megathrust Earthquake of July 29, 2025. Review

On July 29, 2025, an earthquake with a moment magnitude of MW = 8.8 occurred in the Kuril–Kamchatka Trench to the east of Petropavlovsk-Kamchatsky. This earthquake ranks among the ten strongest instrumentally recorded seismic events in the world. For the first time, a megathrust earthquake of such magnitude (greater than 8.5) caused no human casualties or mass destruction. This was largely due to the advanced implementation of preventive measures on the territory of Kamchatka Krai. These measures included the targeted strengthening of the seismic resistance of buildings and structures, as well as the enhancement of alert and population evacuation algorithms. The scientific basis for planning these seismic safety measures was provided by the long-term earthquake prediction carried out by Academician of the Russian Academy of Sciences Sergey A. Fedotov. This paper is devoted to a contemporary reassessment of the results of long-term earthquake prediction for the Kuril–Kamchatka island arc by S. A. Fedotov in the context of the 2025 Kamchatka megathrust earthquake. The paper details the development and evolution of the method, which is grounded in the concepts of seismic gaps and the seismic cycle. The cycles of seismic activity and seismic energy release in the source area of the strongest earthquake, as constructed by S. A. Fedotov, together with the foreshock–aftershock scenario, are presented. The paper describes the long-term earthquake predictions for five-year periods and provides an overall assessment of their reliability. It is shown that, since 1965, the sources of all earthquakes with M ≥ 7.75 have occurred within the seismic gaps that S. A. Fedotov had identified as the most probable areas of the future strongest earthquakes. The source of the 2025 megathrust earthquake originated in a region that, as early as the beginning of the 1980s, had been identified as one of the segments of the Kuril–Kamchatka Arc where the next strongest earthquakes were expected. According to a refined prediction made in 2019, the probability of a megathrust earthquake occurring in that area within the following five-year period was estimated at 50.4%. Thus, the long-term earthquake prediction method by S. A. Fedotov has been successfully verified by a planetary-scale event. The 2025 Kamchatka megathrust earthquake has convincingly confirmed its fundamental tenets, indicating the high predictive efficiency of the method.