New Zealand Journal of Geology
and Geophysics abstracts
Seismic scattering signatures
of small-scale heterogeneities: examples from the Mount Messenger
Formation, New Zealand
Tom Hulme*
John Haines
Bullard Laboratories
Department of Earth Sciences
University of Cambridge
Madingley Road
Cambridge, CB3 0EZ, UK
hulme@esc.cam.ac.uk, haines@esc.cam.ac.uk
Stuart
Henrys†
Institute of Geological
& Nuclear Sciences
P.O. Box 30 368
Lower Hutt, New Zealand
s.henrys@gns.cri.nz
*Present
address: Laboratoire de Géosciences
Marines, Institut de Physique du Globe de Paris, 4 place Jussieu, Paris
75005, France.
†Author
for correspondence.
Abstract Heterogeneity
that is on a length scale just below that of a seismic wavelength is at
the limit of resolution but may still cause significant wave
scattering. A specific instance of this situation concerns seismic wave
propagation through a sedimentary succession. Evidence from a
high-resolution seismic experiment on the Mount Messenger Formation in
North Taranaki, New Zealand, suggests that scattering from small-scale
geometrical variations within the succession may be responsible for the
presence of artefacts in processed seismic sections. Reflection data
for this experiment have a dominant wavelength of c. 20 m, and
the Mount Messenger Formation contains significant lateral variation on
this length scale in the form of channel features. We model wave
propagation through simplified models of these features; the resulting
synthetic seismograms show that scattering and diffraction from
small-scale lateral variation in elastic properties is an important
effect. Simple processing steps applied to the synthetic results lead
to the scattering manifesting itself as artefact in seismic image
sections; these artefacts are analogous to those seen in the field
data.
Keywords scattering;
diffraction; seismic modelling; small-scale heterogeneity; Mount
Messenger Formation
G04034; Received 12 August
2004; accepted 3 June 2005; Online publication date 29 September 2005
New Zealand Journal of Geology
& Geophysics, 2005, Vol. 48:
609–621
0028–8306/05/4804–0609 © The Royal Society of
New Zealand 2005
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