Citation: Aa. Lyubushin et al., ANALYSIS OF THE SPECTRAL MATRICES OF HYDR OGEOLOGICAL OBSERVATIONS ATTHE PETROPAVLOVSK GEODYNAMIC RESEARCH SITE, KAMCHATKA, AND THEIR COMPARISON WITH THE SEISMIC REGIME, Izvestia Akademii nauk SSSR. Fizika zemli, (6), 1997, pp. 79-89