Influence of a dipping crust on the spectrum of "P" seismic waves

Abstract

Recent observations and surveys in different parts of the world indicate that the Mohorovicic discontinuity deviates strongly from the condition of horizontality. It has been known for a long time that the thicknes of the crust is different below the continents than the oceans. This implicates some sloping of the discontinuity along the contact ocean-continent. The same change of the thirkness seems to be present below the chains of mountains. Even below the interior of the continents where mountains are not present, like below the Lake Superior in the U.S.A. (Smith et al., 1966), or below the Southern part of France (Mecheler and Rocard, 1966), sharp changes of the mantle-crust interface have been reported.