The determination of S-wave polarization angles for an earth model with crustal layering

Abstract

This paper presents a method for determining the polarization angle of S waves which takes account of the crustal layering at the seismograph station. Charts are given for four crustal models, corresponding to normal continental, thick, and thin crusts, which enable one to obtain the polarization angle at the top of the mantle beneath the seismograph station. The equations to be used for obtaining the polarization angle are tan ∈ = F h tan γ tan ∈ = F v tan δ where ε is the polarization angle, γ is the angle between the horizontal component of the S-wave surface motion and the great circle path at the station, δ is the angle between the vertical axis and the component of the S-wave surface motion in the plane transverse to the great circle path, and Fh and Fv are functions of wave period, epicentral distance, and the crustal structure at the seismograph station. Values of Fh and Fv for four crustal models are given in the paper.