Energy Partitions of Seismic Waves in Interfaces: Numerical Results

The energy propagated by a seismic event has been of great interest to the community of geophysics and seismologists. In recent times, several studies have been published with the purpose of showing the contributions of each type of seismic wave to the total energy propagated. In this context, diffuse field theory, Green functions and motion correlations have been used to determine energy contributions or partitions based on the type of propagated seismic waves or the degrees of freedom of the medium. In this work, we implement the boundary element method to derive seismic wave energy partitions in interfaces (vacuum–solid, fluid–solid and solid–solid). Theoretical results for two-dimensional infinite spaces show that for a Poisson solid, the energy partitions are 25% for P waves and 75% for SV waves; our results are coincident with such values. However, for interfaces, energy partitions are strongly dependent on the propagation velocities and Poisson's ratio of the media they join. For the case of a vacuum–solid half-space, our results are coincident with those already published and whose energy amplification reaches a value of 2.0 for a Poisson solid.