We derive refraction statics for seismic data recorded in a hard rock
terrain, in which there are large and rapid variations in the depth
of weathering. The statics corrections range from less than 10 ms
to more than 70 ms, often over distances as short as 12 receiver
intervals. This study is another demonstration of the importance
in obtaining accurate initial refraction models of the weathering
in hard rock terrains in which automatic residual statics may fail.
We show that the statics values computed with a simple model of the
weathering using the Generalized Reciprocal Method (GRM) and the
Refraction Convolution Section (RCS) are comparable in accuracy to
those computed with a more complex model of the weathering, using
least-mean-squares inversion with the conjugate gradient algorithm
(Taner et al., 1998). The differences in statics values between the
GRM model and that of Taner et al. (1998) systematically vary from
an average of 2 ms to 4 ms over a distance of 8.8 km. The differences
between these two refraction models and the final statics model,
which includes the automatic residual values, are generally less
than 5 ms. The residuals for the GRM model are frequently less than
those for the model of Taner et al. (1998). The RCS statics are picked
approximately 10 ms later, but their relative accuracy is comparable
to that of the GRM statics. The residual statics values show a general
correlation with the refraction statics values, and they can be reduced
in magnitude by using a lower average seismic velocity in the weathering.
These results suggest that inaccurate average seismic velocities
in the weathered layer may often be a source of short-wavelength
statics, rather than any shortcomings with the inversion algorithms
in determining averaged delay times from the traveltimes.
%0 Journal Article
%1 palmer_jones:2005
%A Palmer, D.
%A Jones, L.
%D 2005
%I Blackwell Scientific Publications
%J Exploration Geophysics
%K geophysics seismics
%N 1
%P 18--25
%R 10.1071/EG05018
%T A simple approach to refraction statics with the generalized reciprocal
method and the refraction convolution section
%U http://dx.doi.org/10.1071/EG05018
%V 36
%X We derive refraction statics for seismic data recorded in a hard rock
terrain, in which there are large and rapid variations in the depth
of weathering. The statics corrections range from less than 10 ms
to more than 70 ms, often over distances as short as 12 receiver
intervals. This study is another demonstration of the importance
in obtaining accurate initial refraction models of the weathering
in hard rock terrains in which automatic residual statics may fail.
We show that the statics values computed with a simple model of the
weathering using the Generalized Reciprocal Method (GRM) and the
Refraction Convolution Section (RCS) are comparable in accuracy to
those computed with a more complex model of the weathering, using
least-mean-squares inversion with the conjugate gradient algorithm
(Taner et al., 1998). The differences in statics values between the
GRM model and that of Taner et al. (1998) systematically vary from
an average of 2 ms to 4 ms over a distance of 8.8 km. The differences
between these two refraction models and the final statics model,
which includes the automatic residual values, are generally less
than 5 ms. The residuals for the GRM model are frequently less than
those for the model of Taner et al. (1998). The RCS statics are picked
approximately 10 ms later, but their relative accuracy is comparable
to that of the GRM statics. The residual statics values show a general
correlation with the refraction statics values, and they can be reduced
in magnitude by using a lower average seismic velocity in the weathering.
These results suggest that inaccurate average seismic velocities
in the weathered layer may often be a source of short-wavelength
statics, rather than any shortcomings with the inversion algorithms
in determining averaged delay times from the traveltimes.
@article{palmer_jones:2005,
abstract = {We derive refraction statics for seismic data recorded in a hard rock
terrain, in which there are large and rapid variations in the depth
of weathering. The statics corrections range from less than 10 ms
to more than 70 ms, often over distances as short as 12 receiver
intervals. This study is another demonstration of the importance
in obtaining accurate initial refraction models of the weathering
in hard rock terrains in which automatic residual statics may fail.
We show that the statics values computed with a simple model of the
weathering using the Generalized Reciprocal Method (GRM) and the
Refraction Convolution Section (RCS) are comparable in accuracy to
those computed with a more complex model of the weathering, using
least-mean-squares inversion with the conjugate gradient algorithm
(Taner et al., 1998). The differences in statics values between the
GRM model and that of Taner et al. (1998) systematically vary from
an average of 2 ms to 4 ms over a distance of 8.8 km. The differences
between these two refraction models and the final statics model,
which includes the automatic residual values, are generally less
than 5 ms. The residuals for the GRM model are frequently less than
those for the model of Taner et al. (1998). The RCS statics are picked
approximately 10 ms later, but their relative accuracy is comparable
to that of the GRM statics. The residual statics values show a general
correlation with the refraction statics values, and they can be reduced
in magnitude by using a lower average seismic velocity in the weathering.
These results suggest that inaccurate average seismic velocities
in the weathered layer may often be a source of short-wavelength
statics, rather than any shortcomings with the inversion algorithms
in determining averaged delay times from the traveltimes.},
added-at = {2012-09-01T13:08:21.000+0200},
author = {Palmer, D. and Jones, L.},
biburl = {https://www.bibsonomy.org/bibtex/2e897de7f0076d44b0592f32b685efffb/nilsma},
doi = {10.1071/EG05018},
interhash = {cafbbc173fb533618302a24a679c95bd},
intrahash = {e897de7f0076d44b0592f32b685efffb},
journal = {Exploration Geophysics},
keywords = {geophysics seismics},
number = 1,
pages = {18--25},
publisher = {Blackwell Scientific Publications},
timestamp = {2021-02-09T13:27:11.000+0100},
title = {A simple approach to refraction statics with the generalized reciprocal
method and the refraction convolution section},
url = {http://dx.doi.org/10.1071/EG05018},
volume = 36,
year = 2005
}