\prefacesection{Preface}
The markings [ER], [CR], and [NR] included in the figure captions in
this thesis denote the extent to which each figure is reproducible by
anyone desiring to do so.  The electronic version of this
thesis\footnote{http://sepwww.stanford.edu/public/docs/sep128}
provides the original figures and Fortran90 programs written to
produce all of the results.  Most programs are included locally in the
chapter directories.  The ShotMig directory contains my
split-step Fourier plus interpolation shot-profile depth migration
program.  I assume you have a UNIX-based workstation with Fortran90,
and C compilers, an X-Windows environment, and the Stanford
Exploration Project (SEP) software available from our website (make
rules, programming libraries, and \LaTeX\ packages).
\par
Reproducibility is a way of organizing computational research that
allows both the author and the reader to verify and regenerate
results.  Reproducibility also facilitates the transfer of knowledge
within SEP and between SEP, its sponsors, and the geophysical
community at large.  
\begin{description}
\item [ ER ] 
        denotes Easily Reproducible results of processing described in
        the paper.  I claim that you can reproduce such a figure from
        the programs, parameters, and makefiles included in the
        electronic document.  The data must either be included in the
        electronic distribution, be easily available to all
        researchers (e.g., SEG-EAGE data sets), or be available in the SEP data 
  library\footnote{http://sepwww.stanford.edu/public/docs/sepdatalib/toc_html/}.
        Before the publication of the electronic document, 
        someone other than me tested my claim by 
        destroying and rebuilding all ER figures. 

\item [ CR ]
        denotes Conditional Reproducibility.
        I certify that the commands are in place to reproduce
        the figure if certain resources are available.
        CR results have been tested to make sure that 
        the makefile rules exist and the source codes referenced 
        are provided.  Conditional reproducibility applies to
        figures produced with excessively long or parallel computing
        processes or when using proprietary data.

\item [${\rm \bf M}\;\;\;\;$]
        denotes a figure that may be viewed as a movie in the web
        version of the report.  A movie may be either ER or CR.

\item [ NR ]
        denotes Non-Reproducible figures. SEP discourages authors from
        flagging their figures as NR except for figures that are used
        solely for motivation, comparison, or illustration of the theory,
        such as:  cartoons, drawings, scans, or figures taken from other
	publications.
\end{description}
Our testing is currently limited to LINUX 2.4 (using either
the Intel or Portland Group Fortran90 compiler), but the
code should be portable to other architectures.  Reader's
suggestions are welcome.  For more information on reproducing SEP's 
electronic documents, please visit 
\newline {\tt http://sepwww.stanford.edu/research/redoc/}. 

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