SPECTRAL and SOURCE PARAMETERS of NORTH CAUCASUS EARTHQUAKES in 2018–2019

Abstract

The dynamic parameters of the sources of 44 earthquakes in the North Caucasus were determined from the amplitude spectra of S-waves for the period 2018–2019 with an energy class according to T.G. Rautian scale KR=9.1–14.1. Earthquake records from regional digital seismic stations of the North Caucasus network, with epicentral distances of no more than 300 km were used for the calculation. The source spectra were calculated based on the frequency-dependent quality factor Q(f) for earthquakes in the North Caucasus western zone – Q(f)=90f 1.02 – and eastern zone – Q(f)=97f 0.89 . The SEISAN program was used for the spectral analysis of 31 earthquakes. The following values were obtained: 0 – spectral density, f0 – corner frequency, M0 – scalar seismic moment, Mw – moment magnitude, L – length of the rupture at the source of an earthquake, or r – radius of the circular area,  – stress drop. Relationships between lgM0 and KR and Mw and KR are obtained.