ESDB100027 2025120214330000 Vladimir Kaftan crossref@gcras.ru Geophysical Center of the Russian Academy of Sciences Geophysical Center of the Russian Academy of Sciences Peter Dokukin People's Friendship University of Russia Vladimir Kaftan Geophysical Center RAS N. N. Titkov Kamchatka Branch of the Federal Research Center of the Geophysical Survey of the Russian Academy of Sciences, Petropavlovsk-Kamchatsky, Russia D. V. Chebrov Kamchatka Branch of the Geophysical Survey of the Russian Academy of Sciences, Petropavlovsk-Kamchatsky, Russia A spatiotemporal analysis of total shear strain was conducted using a continuous regional GNSS network of twenty-two stations over the five years preceding the Kamchatka megathrust earthquake. The presented synoptic animation demonstrates the consistent behavior of seismicity and total shear strain over the five years preceding the strongest earthquake. Coordinate solutions for stations located on the Kamchatka Peninsula and the nearest islands, which are part of the regional KAMNET network, were provided by researchers from the Kamchatka Branch of the Unified Geophysical Service of the Russian Academy of Sciences. Coordinate data for the remaining stations in Russia, Japan, and the USA were obtained from the web archive of the Nevada Geodetic Laboratory (Reno, USA) [Blewitt et al., 2018]. The time series of GNSS station coordinates begins on January 1, 2020, and ends immediately after the Kamchatka megaquake of July 30, 2025, with an M8.8 magnitude. A total shear anomaly began to form two years after the initial observation period in the south of the region. It is likely caused by pressure from the Pacific Plate. Relatively higher seismicity was observed here at the time, as evidenced by the accumulation of earthquake epicenters. A year later, a new anomaly began to accumulate near Bering Island. Here, the GNSS station is subject to the most rapid horizontal motion. Until the occurrence of the megathrust earthquake, both anomalies increased to 1.5*10-6. After the occurrence of the strongest event, these areas merged. This behavior suggests the possibility of a two-side triggering action of these anomalies on a mature seismic source, as for example in [Kaftan and Melnikov, 2019]. The video clearly demonstrates the existence of a deformation gap precisely in the area of the future seismic rupture. 2025 12 02 2025 Geophysical Center of the Russian Academy of Sciences Moscow, Russia Geophysical Center of the Russian Academy of Sciences Moscow, Russia 10.2205/esdb-kamchatka-tss-2025 2025120214330000 https://esdb.wdcb.ru/doi/2025/esdb-kamchatka-tss-2025.html