Problems of Engineering Seismology: article

Аnnotation: In the author’s early works, a mechanical-mathematical method has been developed for modelling strong earthquake synthetic seismograms and accelerograms for a given site with certain ground conditions, whereby an earthquake is viewed as an effect of instant rupturing of Earth’s crust. This study examines ground displacements, velocities, accelerations, and relative shear strains, as well as earthquake response spectra based on synthetic accelerograms. All ground categories are reviewed, from the hardest rocks to the loosest grounds. The maximum values for ground displacements, velocities, and accelerations are obtained depending on the attenuation coefficient of the rocks and the number of the considered foundation bedding’s oscillation modes, as well as peak ground accelerations depending on the distance from the expected earthquake’s rupture. It is shown that the higher modes of oscillation increase ground acceleration 1.66 times, if calculated only using the first oscillation mode and they also increase ground displacements 1.1 times, while decreasing shear strain 1.1 times. The maximum positive attenuation effect in hard ground compared to its absence reaches 37%. Shear strain values increase proportionally to the increase of soil category order number. At the level of 15 meters from Earth’s surface in rocky soils, at a magnitude of М = 7.0, the shear strain values exceed the critical thresholds, which implies a high probability of surface rupturing, Response spectra obtained by synthetic accelerograms are compared to similar spectra based on a large number of actual earthquakes, showing that they are quite similar both in qualitative and quantitative terms. Based on the obtained results, it is recommended to use them for assessing the seismic hazard levels at various areas, monitoring for earthquake prediction, ensuring seismic safety of facilities and underground structures, and enhancing the analysis methods of seismic impact on building and structures.