Open AccessSeismic process on the Krillon Peninsula (Sakhalin Island) after the earthquake on April 23, 2017
Author(s) -
А.С. Закупин,
N.V. Boginskaya,
D.V. Kostylev
Publication year - 2021
Publication title -
litosfera
Language(s) - English
Resource type - Journals
eISSN - 2500-302X
pISSN - 1681-9004
DOI - 10.24930/1681-9004-2021-21-5-734-742
Subject(s) - seismology , aftershock , epicenter , induced seismicity , geology , peninsula , radon , earthquake swarm , intraplate earthquake , seismotectonics , geography , tectonics , physics , archaeology , quantum mechanics
Research subject and methods. The seismicity of the Krilyon Peninsula (Sakhalin Island) after the earthquake on April 23, 2017 (M = 5.0) during the 2018–2021 period was investigated by the method of self-developing processes (SDP). Results. The seismic activity showed a damping trend after the earthquake (and several following aftershocks), with the activation of SDP seismicity observed in two cases. In the study area (40 km within the radius from the epicenter of the Krillon earthquake) and its immediate vicinity (up to 80 km), earthquakes with M = 3.9 and M = 4.3 were observed 74 and 26 days after seismic activations. These earthquakes are considered to be the strongest events occurred in the study area in the period under consideration. The results of the study were compared with the monitoring data of the Kamchatka branch of the Geophysical Survey Russian Academy of Sciences (KB GS RAS) on the volumetric activity of subsoil radon (OA Rn). It was revealed that the OA Rn anomalies detected in November 2018 and January 2020 had appeared several weeks after the identifed SDP. The anomalies were registered at observation points remote from the study area (as well as from the above-mentioned earthquakes) by no more than 50 km. Earthquakes in 2018 (M = 3.9) and 2020 (M = 4.3) occurred 19 and 32 days after the appearance of OA Rn anomalies. In general, the current situation can be assessed as calm, since, according to the analysis data, the seismic activity has no prerequisites for the transition from the decaying stage to the stage of stabilization. As shown in the work, this is a sign for preparing an earthquake with a magnitude higher than 5. Nevertheless, activation and (as a result) earthquakes of moderate strength (M < 5) are possible on a damping trend. Conclusion. It is proposed to take into account the self-developing processes of activation as a primary sign for a change in the geodynamic state of the environment, under which the appearance of OA Rn anomalies is possible. These anomalies are associated with the forecast of moderate seismicity during foreshock or aftershock activations.