Problems of Engineering Seismology: article

Аnnotation: Estimates of seismic motion induced by remote earthquakes that are necessary for the design and construction of high-rise buildings have been obtained for St. Petersburg. As a remote scenario earthquake, an earthquake was selected with a source located in the Vrancea zone (the Eastern Carpathians, Romania), whose parameters are assumed the same as for Moscow: the moment magnitude MW = 8.0, the stress drop ~320 bars, the source depth ~100 km. Model accelerograms of the scenario earthquake are constructed for the site of Pulkovo seismic observatory in St. Petersburg, and the procedures for recalculation of the accelerograms to other ground conditions are described. For St. Petersburg, we obtained higher estimates of peak ground accelerations during the scenario earthquake than for Moscow, though the epicentral distances are ~250–300 km longer. This is due to ground conditions in St. Petersburg and the surroundings: the crystalline basement lies much closer to the surface than in Moscow, at depths of ~170–190 m, and resonant effects in the sedimentary column significantly amplify seismic motions.