Prediction of seismic impacts at the site of Plavinu HPP from a potential seismic source in Koknese (Latvia)

Abstract

The study considers the impact of seismic waves from the source of a potential earthquake in Latvia on the site of the Plavinu hydroelectric power station, which is located in unfavorable geological, tectonic, and geodynamic conditions. A direct seismology problem was solved in two stages to assess seismic impacts on the site. In the first stage, the modeling of synthetic seismograms was carried out, and in the second stage, a prediction of seismic impacts at the hydroelectric power station site was conducted. In the first stage, we used wave field modeling applying Green's method. In the second stage, ground motion characteristics were obtained using a one-dimensional, nonlinear ground response analysis method. A wave field of 15 Green's functions was obtained, which was then converted into a 3-component accelerogram. The accelerogram was then used as a seismic impulse to a Prequaternary sediment's surface. A set of engineering and seismic characteristics of soil was obtained, i.e. amplification, Fourier amplitudes, and spectral amplitudes. The paper demonstrates the ability to acquire valuable information about the seismic wave field and ground motion from macroseismic data from historical earthquakes. This is especially important for intra-plate conditions with limited seismic statistics. Prediction of engineering and seismic conditions are of great practical importance since they will allow us to identify the most vulnerable sites of the soil at the Plavinu HPP.