Trigger effects of seismotectonic processes in a dynamically changing geological medium

Abstract

Despite significant efforts in research into medium and shortrange seismic hazards, the final result that could allow us to predict a future epicentral zone remains unclear. These forecasts use empirical experi� ence based on laboratory models of material destruc� tion and distinguishing local perturbations of different parameters of the medium. In this work, we analyze the seismotectonic situation based on monitoring data of integral lithospheric parameters reflecting continu� ous variability of the parameters on a regional scale. Longterm experience of monitoring (1) and anal� ysis of geotectonic situations allow us to formulate new goals, which require that two factors be taken into account. The first one is that continuous variations of local and integral lithospheric parameters on various scales (deformation, water level, conductivity, microseismic noise, velocities of seismic waves, weak seismicity regime, and others) are described by a set of harmonics with periods from hours and days to many months and years (2). Such rapid and continuous variations of the medium parameters reflecting the corresponding vari� ations in the volume stressed state (VSS) cannot be associated with the response of the medium to very slow tectonic motions. The nature of fast variations in VSS is considered with the account for the interaction of ascending light gases (hydrogen, helium) with the solid phase (3, 4). When the gradients of lithostatic pressure and temperature are quasiconstant, the influence of mobile ascending flows of light gases becomes the main variable factor controlling the cur� rent VSS variation in the medium. This approach allows us to show that seismicity, including strong seismicity, is caused by weak variations (fluctuations)