10.6084/m9.figshare.3454907.v1
K. W. Helen Lau
K. W. Helen
Lau
R. S. White
R. S.
White
P. A. F. Christie
P. A. F.
Christie
Integrating streamer and ocean-bottom seismic data for sub-basalt imaging on the Atlantic Margin
Geological Society of London
2016
velocity model
OBS
reflection data
image
Such flows attenuate
NW
3 D datasets
uniform flood basalt sequence
LVZ
Atlantic Margin ABSTRACT
Geology
2016-06-22 11:31:38
Dataset
https://geolsoc.figshare.com/articles/dataset/Integrating_streamer_and_ocean-bottom_seismic_data_for_sub-basalt_imaging_on_the_Atlantic_Margin/3454907
<p><strong>ABSTRACT</strong> Stacked basalt flows cover much of the NW European continental margin, including potentially prospective sediments of the
Faroes shelf. Such flows attenuate seismic energy, hindering sub-basalt structural imaging which is critical for both exploration
and tectonic studies. Low-frequency, long-offset reflection surveys have yielded improved images below top basalt, while coincident
ocean-bottom seismometer (OBS) data have mapped low velocity zones (LVZ) from tomographic inversion. Image correlation in
a common depth domain is challenged by low spatial resolution of the tomographic image, the absence of turning rays in a LVZ
and the lack of wide-angle arrivals in the reflection data. We integrate densely sampled reflection data with deep velocities
from OBS data to give a common velocity model in a new, iterated, pre-stack depth-migration workflow using complementary constraints
from the two datasets. The matched velocity model and depth image enable interpretation of (i) a uniform flood basalt sequence,
2–4 km thick beneath the Fugloy Ridge, with velocities correlating with those in the Lopra 1/1A borehole and (ii) a sub-basalt
LVZ with chaotic reflections corresponding to sill-intruded, probably syn-rift sediments. Such a workflow could be extended
to targets beneath high velocity salt or basalt and could provide constraints for 3D datasets.
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