Centroid Moment Tensor of the Kamchatka Earthquake on July 29, 2025 Determined on GNSS Data and ISOLA Software Package

Using the example of the Kamchatka earthquake on July 29, 2025, this study demonstrates the ability to determine the centroid moment tensor (CMT) of a strong earthquake based on GNSS records at regional distances. We used the ISOLA software package, which is typically used to obtain CMT solutions for weaker earthquakes. The CMT solution obtained using GNSS data agrees well with the solutions from leading global seismological agencies that used seismic records at teleseismic distances. It is also comparable to the CMT solution obtained by the authors based on seismic data from regional seismic stations. Due to the wide selection of GNSS observation point displacement records, which significantly exceeds the number of seismic observation points with broadband equipment, it was possible to obtain a better centroid location. The fact that there are no restrictions on the lower frequencies of the earthquake wave spectrum in GNSS records allowed us to determine the magnitude of the Kamchatka earthquake with high accuracy. The use of GNSS records in conjunction with traditional seismological data can be recommended for inclusion into the procedures of seismological services responsible for registering largest regional earthquakes and warning the population in hazardous areas of the threat of a tsunami.