Investigation of the variation of P-wave amplitudes and d2T/dΔ2 with epicentral distance reveals that the amplitudes in the distance range up to 100° can be represented by seven discontinuous curves. The discontinuous nature of the amplitude curves can be explained due to the possible existence of first- or second-order velocity discontinuities in the upper and lower mantle of the Earth. Seven magnitude relations corresponding to these amplitude curves are given, which yield consistent magnitudes for nuclear explosions as well as for shallow earthquakes.

First Page Preview

First page PDF preview
You do not currently have access to this article.