1.
n. [Geophysics]
A mathematical method to determine seismic attributes, including reflection strength and instantaneous frequency, by using the Hilbert transform, a special form of the Fourier transform, and the quadrature trace, or the component of the signal that is 90 degrees out of phase.
The Fourier transform
a(t) = h(t) + jx(t),
where
h(t) = seismic trace
x(t) = quadrature trace
can be used to determine reflection strength by combining h and x:
r(t) = [h(t)^{2} + x(t)^{2}]^{1/2},
and to determine instantaneous phase:
θ(t) = tan^{−1}[x(t)/h(t)].