Seismic Monitoring in Severo-Kurilsk Before and After the July 29 (30), 2025 Earthquake Based on Data from an Engineering Seismometric Station

In April 2024, an engineering seismometric station was installed in a residential building in Severo-Kurilsk (Paramushir Island, Sakhalin Oblast) to obtain information about the vibrations of structures and adjacent ground areas during earthquakes as part of seismic observations conducted by the Sakhalin Branch of the Geophysical Survey of the Russian Academy of Sciences. Based on the obtained data on the intensity of the Kamchatka earthquake of July 29 (30), 2025, MW = 8.8, in residential buildings in Severo-Kurilsk, the development of the seismic process before and after the earthquake was analyzed. The obtained data were compared with data from a stationary seismic station in Severo-Kurilsk, located 900 m from the residential building. Both stations are equipped with strong vibration sensors installed in different conditions. Of the 1,790 earthquakes (with a magnitude of M ≥ 3.5) recorded by the regional seismic network from July 29 to October 15, 2025, 195 events with an intensity of I ≥ 3.6 impacted residential buildings. Of these 195 earthquakes, 14 had an impact magnitude of I ≥ 6.0, and the main directions of the axes of maximum impact on residential buildings were east–west and north–south. The study results demonstrate that integrating engineering and technical monitoring into the urban environment is an important element of seismic risk reduction strategies and operational decision-making after strong earthquakes.