Analytic Formulae for Vertical Slowness and Tau-P Intercept Time of P-waves in Tilted Orthorhombic Media

We present an analytic formula for the vertical slowness components of down- and up- going P-waves in 3D tilted orthorhombic media. The perturbation method and Shanks transform are used in our derivation. The proposed formula for the vertical slowness components is valid for strongly anelliptic orthorhombic media with tilted symmetry axes. An application of the formula is shown to calculate the tau-p intercept time of P-waves in horizontally layered, tilted orthorhombic media.