SIMULATION OF LOVE WAVES SPACE-TIME FIELDS USING AN ACCELEROGRAM

Abstract

This paper continues a work on simulating of seismic waves fields based a given accelerogram [Stroiyel’stvo i rekonstrukzija 2, 2015, p.p. 20-26]. An algorithm is based on decomposition of original accelerograms in a Fourier series and applied for simulating of the Love waves field. However, there are circumstances that complicate a generation of spatial wave field. Surface Love waves arise in an elastic medium, consisting of a layer lying on a stiffer half-space. Love wave is dispersive, i.e. its phase velocity depends on a frequency; moreover, several waves with different phase velocities can exist to a single frequency. This paper provides an analysis of a dependence of roots of a dispersion equation (phase velocities) on the frequencies and layer thickness; the formulae are derived for the simulating Love wave propagation. A source accelerogram is considered as a set of harmonic waves. For each frequency the phase velocity of the first order Love wave is determined. The result of this simulation is horizontal movement accelerations of ground particles at any point of the layer and elastic half-space. For an example, calculation of seismic field using a record of horizontal movement of Gazli earthquake (May 14, 1976, 2048 points, duration 13.48 c) is considered.