Seismic instruments: article

TIDAL RESPONSE OF THE GEOPHYSICAL MEDIUM AS AN INDICATOR OF THE LEVEL OF SEISMIC STRESS IN THE EARTH’S CRUST
MYASNIKOV ANDREY VLADIMIROVICH
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia, 119234, Moscow, Universitetsky pr. 13
Journal: Seismic instruments
Tome: 57
Number: 4
Year: 2021
Pages: 51-65
UDK: 550.34
DOI: 10.21455/si2021.4-4
Keywords: LUNAR-SOLAR TIDE, AMPLITUDE FACTOR, PHASE PARAMETER, STRESS-STRAIN STATE, ELASTIC COEFFICIENT, THEORY OF ELASTIC RECOIL
Аnnotation: According to the recording of the 75-meter laser interferometer for a 15-year observation period, the deformation component of the lunar-solar tide is distinguished as a result of the reaction of the earth's crust to this tide. The tidal response depends on the mechanical properties of the geophysical medium, or, in other words, is determined by the elastic coefficients at the observation point. If the medium undergoes to variable tectonic or other mechanical loads, then at extreme values, within the framework of the considered concept, the elastic parameters of the medium should depend on the magnitude of this load or the degree of stress state, and thus change the response of the crust to the tide. It is shown in the work that for a quantitative analysis of the stress level, it is necessary to select only the main lunar wave M2 from the total tide. The main advantage of this wave is that, as shown in this work, this wave is less affected by variations in meteorological factors. Moreover, it is necessary to use a complex parameter, namely the amplitude factor and the phase value of the observed tidal wave M2 in relation to the theoretical value of these parameters of this wave. Only a complete set of these parameters makes it possible to assess correctly the level of tension in the geophysical environment and, as a consequence, the ability to predict the formation of an active seismic source in a local zone.