Problems of Engineering Seismology: article

Аnnotation: The paper presents the results of the estimation of seismic quality factor Q of the Earth’s crust and tops of the upper mantle for the Murmansk region in the frequency band from 0.5 to 32 Hz based on data from the automatic regional catalogue of seismic events for 2019–2022. Assessment of the quality factor was calculated by coda wave decay method for 7 stations and more than 5000 local events. The calculations were performed using data on earthquakes and explosions, with approximately 7 times more explosions than earthquakes. In the central part of the study area, the integral coda Q for the 1 Hz frequency increases with depth from a value of 109 ± 33 at 86 km depth to 280 ± 77 at 126 km, following a linear law. Frequency-dependence degree index of the Q value has high values at a depth of about 86 km and decreases by 26% when the depth equals 126 km. It is shown that when using explosion data, it is possible to underestimate the Q value at a frequency of 1 Hz by 25–50%.