Speaker:  Alison Malcolm


Title:  A series approach to multiply scattered waves in inverse problems


Abstract:
In many wave problems, it is assumed that waves propagate away from
the source, reflect once in the region of interest and continue
directly to the receiver.  This assumption is known as the single
scattering assumption and it is ubiquitous because it linearizes the
inverse problem.  In many situations, however, multiply scattered
waves make up a non-negligible portion of the recorded signal.
Treating these waves as singly scattered waves results in artifacts in
the final image.  We have studied a series approach to modeling
specifically seismic reflection data in which multiply scattered waves
are identified through higher-order terms in the series.  By
understanding both modeling and imaging in this framework we are able
to predict these artifacts.  The same series, when modified to account
for illumination effects allows for image improvements, using the
information contained in multiply scattered waves, by solving a
sequence of linear inverse problems.  The two cases (artifact
prediction and imaging with multiples) result in different algorithms
requiring different computational strategies.