Abstract:
The vertical and radial components of a seismic P wave can be
decomposed by a Fourier transform into two sets of nonterminating
sinusoidal waves with one set for each component. The tangent of the
vertical transform divided by the radial transform gives by definition
he apparent angle of emergence for that frequency. The actual angle
of emergence can be calculated from the apparent angle. The change
of the angle with frequency can be obtained by determining the angle
over the entire frequency spectrum of the pulse.
The angle of emergence is only defined for a pure pulse. Just
the short length of uncontaminated signal can be used to calculate the
angle U the signal is interfered with by other signals. The actual
angle of emergence was calculated as a function of frequency for
stations near nuclear explosions. In all cases, the angle varied
with frequency.
