About the Admittance Function Over Passive Continental Margins

The admittance function is a valuable tool for the interpretation of isostatic compensating mechanisms. However, in the transition between continental and oceanic crust several difficulties arise in the comparison between theoretical models and numerical estimates. As a consequence of analyzing such difficulties for the case of the Antarctic Peninsula margin we have arrived at the following conclusions about the admittance function over passive continental margins: I) the amplitude of the admittance has a spiky behavior and does not have an overall decay with increasing wavenumber; 2) if there is no or incomplete compensation of the surface topography the imaginary component is not negligible, the real component may take on negative values, and destructive interference may occur while performing a spectral average, causing a decay that may be wrongly interpreted as the exponential decay predicted by the linear theory.