Method of seismic events hypocenters relocation for central Ukraine

Abstract

Summary The technique of seismic events hypocenters relocation for central Ukraine (particularly for the Middle Southern Bug subregion (so called Pobuzhzhya)) based on the calculated local seismological travel-time tables is presented. For this on the results of the analysis of lithosphere velocity structure of studied subregion, including on the regional DSS sections, a “balanced” averaged horizontally-layered velocity model of the upper lithosphere (the crust and upper mantle – depth 0–60 km) was built. On the basis of this model, a “family” of calculated local seismological travel-time tables (called by us Pobuzhskyy (Pb″)) of the first arrivals of seismic waves for different depths of foci was built. In this case, the “fastest” wave propagation rays for different depths of foci and epicentral distances of up to 500 km as well as corrections for the Earth's sphericity were determined and taken into account. The calculated travel-time tables are used for the refinemen of hypocenter of local seismic events (earthquakes, explosions in quarries and mines, etc.). The efficiency of the constructed travel-time tables is estimated in comparison with the Jeffreys “standard” averaged local travel-time tables used to date for this subregion.