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Exploring the potentials and limitations of the time-reversal imaging of finite seismic sources

Kremers, Simon, Andreas Fichtner, Gilbert B. Brietzke, Heiner Igel, Carene Larmat, Lianjie Huang, and Martin Käser (2011), Exploring the potentials and limitations of the time-reversal imaging of finite seismic sources, Solid Earth, 95-105, doi:10.5194/se-2-95-2011.

Abstract
The characterisation of seismic sources with time-reversed
wave fields is developing into a standard technique
that has already been successful in numerous applications.
While the time-reversal imaging of effective point sources is
now well-understood, little work has been done to extend this
technique to the study of finite rupture processes. This is despite
the pronounced non-uniqueness in classic finite source
inversions.
The need to better constrain the details of finite rupture
processes motivates the series of synthetic and real-data time
reversal experiments described in this paper. We address
questions concerning the quality of focussing in the source
area, the localisation of the fault plane, the estimation of the
slip distribution and the source complexity up to which time-reversal
imaging can be applied successfully. The frequency
band for the synthetic experiments is chosen such that it is
comparable to the band usually employed for finite source
inversion.
Contrary to our expectations, we find that time-reversal
imaging is useful only for effective point sources, where it
yields good estimates of both the source location and the origin
time. In the case of finite sources, however, the time-reversed
field does not provide meaningful characterisations
of the fault location and the rupture process. This result cannot
be improved sufficiently with the help of different imaging
fields, realistic modifications of the receiver geometry or
weights applied to the time-reversed sources.
The reasons for this failure are manifold. They include the
choice of the frequency band, the incomplete recording of
wave field information at the surface, the excitation of large-
amplitude surface waves that deteriorate the depth resolution,
the absence of a sink that should absorb energy radiated during
the later stages of the rupture process, the invisibility of
small slip and the neglect of prior information concerning
the fault geometry and the inherent smoothness of seismologically
inferred Earth models that prevents the beneficial
occurrence of strong multiple-scattering.
The condensed conclusion of our study is that the limitations
of time-reversal imaging – at least in the frequency
band considered here – start where the seismic source stops
being effectively point-localised.
BibTeX
@article{id1637,
  author = {Simon Kremers and Andreas  Fichtner and Gilbert B. Brietzke and Heiner  Igel and Carene Larmat and Lianjie  Huang and Martin K{\"a}ser},
  journal = {Solid Earth},
  month = {jun},
  number = {2},
  pages = {95-105},
  title = {{Exploring the potentials and limitations of the time-reversal imaging of finite seismic sources}},
  year = {2011},
  doi = {10.5194/se-2-95-2011},
}
EndNote
%0 Journal Article
%A Kremers, Simon
%A Fichtner, Andreas 
%A Brietzke, Gilbert B.
%A Igel, Heiner 
%A Larmat, Carene
%A Huang, Lianjie 
%A Käser, Martin
%D 2011
%N 2
%J Solid Earth
%P 95-105
%T Exploring the potentials and limitations of the time-reversal imaging of finite seismic sources
%8 jun
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Printed 12. Dec 2019 07:38