Relation of corner frequency to fault dimensions

The spectrum of the far-field displacement radiation from a conventional fault model has been calculated for comparison with the spectrum calculated from the recent Brune model. The spectrums are generally similar, but some of the details are attributed to different effects in the two models. For example, where the spectrum decays as ω−1 at intermediate frequencies, the effect is attributed to partial stress drop by the Brune theory but to rupture surface shape (width very much less than length) by the conventional theory. Both theories yield an inverse proportionality between the fault dimensions and the corner frequency in the displacement spectrum. The constants of proportionality in the two theories are similar.