Abstract
Prestack migration finds increasing application in processing crustal
seismic data. However, less effort has been made to incorporate slowness
information in the imaging process. The combination of slowness information
with migration leads to an improved image in the depth domain, especially
by reducing migration artefacts and noise. A slowness-driven isochrone
migration scheme is introduced for migration of 2-D seismic data.
Instantaneous slowness information p(x, t) is extracted from the
data using correlation analysis in moving time and space windows.
Slowness values resulting from spatial coherent energy (signal) and
incoherent background noise are distinguished by the simultaneous
evaluation of an instantaneous coherence criterion g(x, t). In slowness-driven
isochrone migration this information is used for locally weighting
the amplitude A(x, t) smearing on the isochrone surface. In particular,
slowness p and coherence criterion g determine position and sharpness
of a Gaussian weighting function. The method is demonstrated using
two synthetic data examples and is subsequently applied to two deep
crustal data sets, one wide-angle (along DEKORP4) and one steep-angle
reflection seismic observation (KTB8506). Both data sets were collected
in the surroundings of the KTB drill site, Oberpfalz, as part of
the German DEKORP project.
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