Nonlinear Crustal Corrections for Normal-Mode Seismograms

We present an efficient and accurate method for calculating local nonlinear crustal effects on the eigenfrequency of free oscillations of the Earth. We implement the method in the calculation of synthetic normal-mode seismograms and demonstrate that neglecting the nonlinear crustal effects in the tomographic waveform inversion leads to velocity models that appreciably overestimate fast velocity anomalies beneath orogenic belts and cratons at 250–400 km depth. Online material: Color versions of figures.